Reposting this from the now defunct PSP general on /vg/.
There's some real useful shit in here.

----------------------------------------- USEFUL LINKS ++

CFW your PSP for any firmware version
I recommend sticking with 6.20 at the latest if you want to avoid reloading your CFW every time you reboot.
http://wololo.net/cfw4dummies/

Emulator Index
http://wololo.net/talk/viewtopic.php?f=47&t=8026
http://wiki.gbatemp.net/wiki/Emulation_on_PSP
Want to play PS1 games?
Get PSX2PSP to convert your ISOs: http://downloads.exophase.com/198/psx2psp-v142/

Plugin Index
http://wololo.net/talk/viewtopic.php?f=28&t=7407

Homebrew Software Index
http://wololo.net/2014/02/15/the-50-best-psp-vita-homebrews-in-2013/

Huge collection of PSP isos and other roms (DDL, no 3rd party file host bullshit)
http://www.emuparadise.me/

Themes Index (Requires CXMB plugin, choose only the themes for your firmware)
http://wololo.net/talk/viewforum.php?f=27

To put emulators/homebrew on your PSP, simply drop it in the \PSP\GAME folder.

PPSSPP: free and open source PSP emulator for Windows, Linux, Mac, Android, iOS, Blackberry and more.
http://www.ppsspp.org/downloads.html
Makes the 3D graphics look much better than the real thing, but latency is still terrible for rhythm games.

Flash Cart zum spielen von spielen auf nintendo ds geräten - ds bis 3ds

Wie benutzt man die supercard ds2 zum emulieren von gba spielen

Isos, Roms etc.

Wiki mit infos zu emulation von verschiedenen konsolen

Der Nachfolger der Open Pandora - Die DragonBox Pyra