This was first rumored a while ago. Here is the link:
And this is the website tyrone got it from:
The actual document that was leaked obviously has been removed, but it did in fact have info regarding this. Personally, I've believed that Sony would bring a PS2 emulator at some point anyway. Sure, they've said PS2 playback is never, ever coming back, but they have lied about other things before, so I no longer take their official statements to heart.
EDIT: In response to the person who posted below me:
1. That Joystiq link was from 2008 and isn't relevant to this issue. The rumors regarding the PS2 titles and Dreamcast stuff that is the topic of this question was from a couple months ago of this year (and I'm pretty sure Sony has yet to make any confirmation or denial on the issue).
2. Sony denied the $100 price drop, but it happened anyway.
A couple years ago, Sony denied the existence of a 40 GB console before they announced it a couple weeks later.
Sony initially denied the existence of the PS3 Slim.
The fact that Sony seems to deny every rumor involving the PS3 does not mean much.
Also, Koller's statement was made BEFORE this document was leaked by Sega. Plus I actually got to see a little bit of the leaked document before it was removed from the internet and the quoted material listed is accurate from that document and is essentially refuting what Koller said. Koller's statement is exactly the kind of statement that I'm not just gonna accept because Sony has indeed flat out lied in the past when making similar statements. Again, the price cut and the existence of the 40 GB console are great examples (more so the price cut). Dualshock rumble is another one; Sony practically made it sound unfeasible to do in the Sixaxis controller initially.
I'm not trying to say I'm right here. Just trying to say that statements made my Sony are not exactly the truth half the time and the leaked document looked to be some awfully good contradictory evidence on the matter (not to mention it helps support the patent filings of Graphics Synthesizer emulation on the PS3, which was made public in August, and is the one thing left in order to get a 100% software PS2 emulator).