Think about it, the original PSX was released in 1994, and it's not until last year (2000) that we get a decent playable PSX emulator.
So, it takes 6 years.
Now, considering that the PS2 just came out recently, AND its architecture is a million times (well, I'm exaggerating here) more complicated than the PSX, it'll take a few years before we see a playable PS2 emulator.
Oh yeah... you'll probably need a dual Athlon7 5.6GHz and a GeForce 6 Ultra or an ATI 95000 with 1.5G of RAM to run it well.
It outlines the fundamental differences between the pc cpu and the emotion engine. (Data driven design VS Instruction driven design). You should check it out if your wondering how hard/challenging confused: ) it would be to create a ps2 emulator, as well as understand some potential bottlenecks in achieving this.
The DC-Emulation is poor at the moment, too, and it's even older than the PS2. Besides that it would take *really* big PC it would take Years until they're will be any PS2-Emu which can play a commercial game. That means that i'll have to buy a real PS2 to play FF10
The architecture of the ps2 is so dramatically different from a pc right now that emulating it would be nearly impossible.. The pc uses large caches and small bandwith while in comparison, the ps2 uses little caches and a huge bandwith.. Thats why a lot of game programmers has had problems with programming for the system.. They need to get use to programming for a huge bandwith and small caches of the ps2.. Maybe when the bandwith specs of pc's start surpassing the ps2 then we may see a ps2 emu emerge..
At first there was a fake-emu "Nightmare".
A french site also released a fake with a "system-rom (also fake)" but I cannot remember the name - this one contained possibly a worm.
But there is something like a PS2-Emu. This Emulator was given out to developers of PS2-Software a long time before the first PS2 came out. This one was told to be extremely slow. It was quite big with (cross-)compilers and so on - nothing of interest. Somewhere else I read that Connectix seems to work hidden on a PS2 emulator called VGS2.