The only way you could get actual pinpoint accuracy with the Wiimote is to have three separate sensor bars, which you would have to place in some configuration (three corners, one corner and two sides, etc) such that the Wiimote can triangulate its exact location to in relation to the screen.

As it currently stands, it makes a rough estimate, as it has no realistic way to obtain the exact specs of the screen (though some games do recalibrate for accuracy, such as Super Monkey Ball)

Actually some games come with calibration, the one I know is Zelda. Also, do everything that Kwaad said and everything should be fine.

 You have much better English than a lot of native speakers on this board. ;)

to be honest, I was thinking of making my own sensor "bar", but without the bar, and rather just two infrared sources that can be moved independently of each other. That way, if I move them further apart, hopefully the Wiimote will think I'm moving less and compensate for it.

That's my theory anyway, I'm not sure exactly how the sensor bar works though.

anyway, I'd really kill for some kind of calibration.

This isn't how the Wiimote is supposed to work.

You watch the "cursor" on the screen - not point there with the Wiimote (i.e. like a gun).

It has nothing to do with the size of the TV or the "quality" of the sensor bar. All the sensor bar does is provide a calibration point, such that the Wiimote knows "roughly" where your TV is.

To work the other way, the sensor bar would have to work out where you are in the room - with the Wiimote - where the TV is, how big the screen is, etc. It doesn't do any of this. Its not supposed to.

Watch the on-screen indicator, and play from that. 

Wait Zelda and Super Monkey Ball have calibration? Can anyone tell me if these games can obtain pixel perfect aim? I think it's more than possible that the Wii can improve over it's lifetime. Didn't the superscope have calibration. Different technology I know, but it makes so much sense. I gotta fix my aim before Metroid comes out. Also I just want to say that there are differing oppinions as to the sensor issues in this thread. I'm still confused.

Zelda has calibration. You press (-) or (+) until the bar on the screen is the same size as the actual sensor bar, and that (alone with the 4:3/16:9 setting) will tell the game the "exact" dimensions of your TV and allow for better pointing. I put "exact" in quotes because it's just an eyeball-shot of how close the on-screen bar is to the real sensor bar, but it's pretty good and I'm surprised all games don't do something like that.

Okay that gives me hope for future games. Seriously I mush have messed up my hookup cause the onscreen pointer is sooo off on my TV. My roommates didn't seem to care though and had a blast when I got my Wii. My friends girlfriend is sore still from playing the Wii, and that was 2 days ago. I am praying for calibration for Metroid.

 Wait... you guys haven't been getting pixel perfect aim?  My friends complained it was too perfect for shooting games...  made the aiming way too easy...  I have to agree... 

The other best bet for anyone having issues is to pick up one of those wireless sensor bars...  apparently some of them use brighter lights and you can literally put them anywhere...  Check a review before you buy though.

It's usually not pixel perfect for most of us when we play multiplayer games...but we don't care...we understand how it works, and we have fun. In Red Steel, it wasn't like we were pointing exactly where we wanted to shoot...we treated it more like a mouse, not a gun. Which is still lots of fun, and you're still relatively pointing to where you want to shoot, so it still rocks.