"A PS2-compatible patch may come later, but it's still hazy since not all PS3s are backwards compatible with PS2 discs. It would sure be great for PS3 owners to have access to the considerable library of PS2 SingStar games, though"

You're not quite right on this one: Sony already announced such a patch for "later this year" (so I quess it is going to be somewhere August-September 2009...) This patch will, according to Sony, allow ANY retail PS3 Model to play PS2 Singstar discs, as it will only read the songs, and stay "inside" of the ps3 game.



Here's the relevant link to the playstation blog: http://blog.us.playstation.com/2008/08/21/how-it-works-singstar-ps2-ps3-compatibility/

Right. My understanding of the original announcement that you linked to is the PS3 version of the game would read the data files off other discs. The patches are to update the PS3 engine to be compatible with the file format of the older data files. You don't need to be able to run any actual PS2 code if all you are doing is reading a file format, everything will happen in the PS3 game engine.