Harmonix is the developer and EA is the Publisher of Rockband.

@oxymeth

The activision guitar would be fully compatable in the rockband game if harmonix had taken the time to use nintendo's wii remotes in the peripheral. me being able to use my guitar on frets of fire is proof of that.

I remember reading a while ago that Harmonix developed a patch to allow the GH3 guitars on the ps3 for rock band. But Activision wanted money$$ for the patch, so they never released it.
As far as I know, its the same reason, Activision want money for using thier guitars on another game. Seems a little rediculous if it is true, as activision will be crying when they release drum hero or band hero, and suddenly the coin is flipped.

Or you could say the Rock Band guitar would be fully compatible with Guitar Hero III if Red Octane hadn't changed their own design unnecessarily to incorporate the Wiimote into it. It woks both ways. The bottom line is that Activision is probably to blame for this. It's well documented that Red Octane, the makers of the Guitar Hero III guitar don't want it to be associated at all with Rock Band. It's also well documented that when the PS3 was having compatibility issues, Harmonix created a patch for the guitars to be workable for either game, but Activision held out for money. Here's links to prove everything I'm saying is what happened:

http://gizmodo.com/gadgets/say-it-ain.t-so/activision-roadblocks-ghiii-guitar-support-for-ps3-rock-band-333279.php

http://blog.wired.com/games/2007/12/harmonix-activi.html

http://kotaku.com/gaming/rock-band/red-octane-talking-trash-over-rock-band-guitars-331082.php

Is it too much out of the realm of reality that Activision and Red Octane again don't want their guitar being used for Rock Band? It seems in the case of the PS3, Harmonix did everything they could to share. Who's to say Activision isn't blocking Harmonix from releasing a patch again?

First: You are right about the guitar compatibility being easy to do in software.  The Les Paul guitar controller for the Wii works exactly like the classic controller (in fact in GlovePIE, you just map the classic controller buttons to make it work).  Second: Did EA lie about that?  Did they actually make a public statement that they can't do it because of X Y or Z?

@onyxmeth, every design change can be considered "unnecessary", but many design changes make products better.  Personally, I like having my guitar able to vibrate and play sounds out of the Wii Remote, and I also like having a more accurate tilt sensor.  And I'm sure it was cheaper for them to make, since the wireless and tilt sensing functionality was already included in the Wii Remote.  Regardless of that, the design of the controller is not a barrier to compatibility.  All the game has to do is support the classic controller -- easy as pie for a game developer.  The problem is purely a licensing issue that needs to be worked out between the publishers and developers.

P.S. If I were Activision, I wouldn't hold out for money.  I think the Les Paul controller is vastly superior to the Fender controller, and if I allowed compatibility for free, I would expect Rock Band owners to buy more of my Les Paul controllers, giving me more profit.  Based on your third link, I wonder if Activision isn't asking for money, but refusing to support the Fender in their games because they want to sell more Les Pauls.

Oh, Wiili.org, I haven't logged on to that site for ages... But yeah, I did the exact same thing (only with a bluetooth adapter for my PC) but it's still a little buggy (I have to run it in a window or it gets choppy) That's how I play Ocarina w/ Twilight Princess Controls...

@entroper
in the announcement about the reklrease date for Riockband PR all but pointed the finger at Actvision by saying that all compatabiliy questions should be directed at that company. However as you pointed out the classic controller support is all that is needed to get the Les Paul working and I am pretty damn sure that Activision holds no patent on the software that supports it. This is still purely a lazy port of an awesome game and Harmonix/EA are responsible.

Well, it makes absolutely 0 sense for PS3 version to not work at all between GH3 and Rockband, while 360 versions do.

That's what pisses me off, they could so very easily make a patch.

Yes, they might lose a few sales, but gain MUCH MORE goodwill.

This is the Quote that pisses me off the most direct from Harmonix PR department

Will Wii's Rock Band be compatible with Wii's Guitar Hero III guitar?
Harmonix and MTV Games believe in an open standard philosophy of hardware and game compatibility. We think that there should be interoperability between music instrument controllers across all music games. This is clearly in the best interest of consumers, game developers and console manufacturers and will only help to grow the music game genre as well as inspire innovation and creativity. Third-party developers and publishers are welcome to freely support the Rock Band peripherals in their games. Support for the GHIII guitar peripherals in Rock Band on the Wii was not possible without Activision's permission. Therefore, any questions regarding lack of compatibility with GHIII hardware should be directed to Activision. [In other words: No. Check out our updated 'Guitar Guide' for complete compatibility details.]

link:
http://www.joystiq.com/2008/03/24/rock-band-wii-drum-kit-pictured-nagging-questions-answered/

So as you can see they are trying to use the same excuse that they used for the PS3 (Which I believe was fully justified), however, this time it is not and they should own up to it orfix it. My expirience proves that all they needed was Wii Remote support for the Activision Guitar to work---- End of story 

After ditching online play and DLC, I was already not going to buy the game

Now, with no Character Customizations, A forced Re-buyal of instruments, and all the other PS2 crappyness...

HARMONIX CAN SUCK MY LEFT NUT AND EA CAN SUCK MY RIGHT, and I STILL WON'T BUY THE GAME!!!

No DLC is Nintendo's fault. Even if they allowed it, there isn't enough space because of no hard drive. Harmonix not only created the GH franchise, Rock Band is a great game. It is Activision's loss that they aren't allowing GH controllers to work it Rock Band because I would have bought GH3 just for the extra guitar and game. As it is now, I'm waiting until I want another Guitar from Harmonix because any song in GH3 that I like I would just want it in Rock Band because singing and drumming are more fun. Just get a PS3 or 360 and stop complaining. Being upset that a Wii game doesn't have online features or DLC is just ridiculous to me. Next people will be complaining about load times and not being able to install games. Or no HD support. Ugh.