www.rom-world.com
www.romnation.net
www.coolrom.com
All three of those are good places to get Roms and Emulators. Remember though, do not download the rom unless you own the original cartridge/disc/other form of media.
www.psp-hacks.com
www.pspupdates.com
www.fanjita.org
Three good resources for other PSP hacking adventures.