JPCSP is the best PSP emulator out. It plays BBS a little bit, but good luck getting the game to even boot (you either need a real PSP or find an already unencrypted image of the game). As it is, don't bother to try for another year or two. Especially if you don't have a fast PC. The game is just barely starting to work on the emulator. It'll probably be another year or two before i'd consider it "playable". From what i hear, it's rather slow, has tons of sound issues, and might even freeze or crash in some parts of the game.