How do i get my 80 GB PS3 to play kingdom hearts 2 or any ps2 games?

It depends on what type of 80 gig PS3 that you bought the ones with the price drop don't play PS2 games $399.99

check the model number in the back, if it says CECHE01, then it should play your PS2 game. However, as indicated in box, it won't play 100% of PS2 title. Not all 80GBs are backwards compatible. If you got your 80GB PS3 at $399 with only 2 USB ports, then it's not the one that plays PS2 games. It's the upgraded version of 40GB which has no backwards compatibility with PS2.

u probably got the $399 80gb,unfortunately this one does not play ps2 games only the $499 with mgs 4 has ps2 bc

Sony decided to make things confusing. (gee, thanks Sony.) There are now 2 models of PS3 that have a 80GB hard drive. The old model comes with MGS4 and is (partially) backwards compatible with PS2 games. It costs $499. The new 80GB PS3 is based on the 40GB PS3. It may have a larger hard drive, it is NOT able to play PS2 games. It costs $399. Once the 80GB PS3 + MGS4 bundle is sold out, that's it. Going forward, all future PS3s - regardless of hard drive size - will be unable to play PS2 games. There is no way to make these PS3s backwards compatible. Sony will have to release a software emulator to enable these models to play PS2 games, but it's doubtful that Sony will ever do this. After all, they'd rather you buy the more expensive PS3 games for your PS3. If playing PS2 games is still important to you, either return the PS3 and pay the difference for the PS3+MSG4 bundle, or, as Sony literally said "If you want to play PS2 games, just buy a PS2!" (gee, thanks Sony...)

in NZ 80gb doesn't have backwards compatibility.

PS2 --> BEST FOR PS2 Games PS3 80 GB --> BEST BUT NO BACKWARD COMP. 60 GB EBAY.COM ONLY --> BEST WIFI WITH BACKWARD COMP. 40 GB --> BEST BUT SAME WITH 80 GB 20 GB --> GOOD WITH BACKWARD BUT NO WIFI