Yaupspe is a cross-platform PSP emulator, based on Potemkin.

It's in intensive development, but there's still work to do: only some PSPSDK samples & homebrews work.

Forum: http://www.emunewz.net/forum/forumdisplay.php?fid=98 IRC channel (chat): #yaupspe on irc.freenode.net ; you can also use http://java.freenode.net/index.php?channel=yaupspe

A very useful emulator, which I took inspiration from: http://code.google.com/p/jpcsp/