this is still a rumor ...

but

1/ I hope this is true

2/ I hope I will NOT have to REbuy online all my PS2 games ... In this case, I go buy 10 Xbox360 and 10 Wii ...

HappySquirrel pretty much summed it up (there is an additional problem with the PS2 ram architecture that adds to the problem. The amount of raw power required also heavily depends on the cpu structures, I remember a Mac emulator for the Amiga which sort of worked 1.1 since it had to emulate the same processor architecture). So the question is: Why would Sony invest a lot of time and a lot of money into something that could, at best, fully work with about 10% of existing PS2 software and approximately work with another 20% of software? Yes, companies have done stupid things but other than yelling "look what a cool thing we did - we can emulate almost 20% of PS2 software", there is nothing Sony can gain by wasting that time and money on an emulator (insofar as readding the PS2 GPU chip to the PS3 board probably costs less than $20 and gives you 99% compatibility, so there is even less incentive to do an emulator).

You do realize the 80 gig PS3 already does PS2 software emulation, right?  The original 20 gig and 60 gig PS3's actually had the emotion engine.  The EE was value engineered out of the 80 gig in favor of software emulation of PS2 games.  Only the 40 gig lacks any sort of PS2 support.  Many believe that that was more of a marketing decision to differentiate the price points/value of the 40 gig, 60 gig, and 80 gig offerings at the time.  Now that Sony has officially killed the 60 gig (this is a shame), they are left with 2 sku's.  This is why many people believe that Sony will offer PS2 compatability in the 40 gig via an unlock patch. 

 It is a rumor, but I have always believed Sony would offer PS2 bc in all of their sku's.  This is vital if they want third parties to continue to support PS2 titles. 

I think NOBODY except Sony knows. =)
Possible or not, it`s not for us to decide. =]

You do realize that the 80Gb (NTSC) still retains the PS2's GS chip so the SKU only needs to emulate half the equation right?

You do also realize that the 40Gb (NTSC/PAL) has neither the EE nor the GS requiring the PS3 to emulate both right?

No, of course you don't. Research more please.

Microsoft did it with the 360, although I don't know if this was based solely off of software or a combined hardware/software approach. That system needs more resources than the PS2 does, although its architecture is admittedly more similar to a PC.

The 80GB Playstation 3 still includes the Graphics Synthesizer (the PS2's GPU) which means that they only have to emulate the Emotion Engine in software.

Being that Microsoft designed both the XBox and XBox 360 to use DirectX (which acts as a hardware abstraction layer) the XBox 360 only has to emulate the XBox's CPU and can "Translate" all of the calls to DirectX and let the XBox 360's GPU handle it. In order to get their 'wonderful' level of compatibility for the XBox on the XBox 360 Microsoft bought a company which focused on emulating x86 processors on powerPC based Apple PCs; in other words, they had a team of people who were experienced (and existing software which was focused on) performing the emulation they needed done.

Basically, no system that I have heard of included software backwards compatibility of their previous generation system without having previous generation hardware unless the GPU of the previous generation system was entirely handled through a hardware abstraction layer.

And this is a big part of the reason why many Xbox games aren't on the BC list yet. Any game that went around DX to get as close to the metal as possible, and thus the best performance possible, are going to be nearly impossible to emulate properly. This is especially true of the games which took advantage of hardware quirks, or undocumented hardware behavior. Since these things are generally only known to the developers getting it emulated properly is going to require a very accurate low level emulation or figuring out what the hell the developers did. 

Now my understanding of the PS2 is that this situation is even worse. Since Sony had absolutely terrible dev kits early on many developers started using the hardware in ways it was never intended to be used. This is something that not only happened with shovel-ware developers, but also top-tier studios squeezing every last ounce of power out of the PS2 - stuff like GOD2, BLACK, or the Rise of Neo (which had normal mapping). Using undocumented or flawed behavior requires the emulator to be very, very accurate at duplicating the behavior of the original hardware. Sometimes these exploited flaws are so minute that hardware redesigns will actually prevent games from playing correctly, and this actually happened with the PS2. 

In other words a practical PS2 emulator that works with most games would have to written very well at a low level. To get good performance it would likely have to be a high level emulator. Since these two are incompatible its likely that there won't be a pure software PS2 emulator on the PS3, or it will be of low quality. 

Furthermore Sony is focused on profitability, and I can't see the justification for spending tons of money on BC when they are outselling the 360. In addition surveys have shown that few people use BC on systems that offer it, and those who do generally own the previous system. 

i really hope it's true, cause i want to get rid of the Ps2.... :P