If you're a fan of arcade games and willing to put in a little time compiling a program to run it, then MAME4ALL is right up your alley. Franxis has released the source code for versions 4.6 and 4.7. These optimized versions of MAME is based on the gpx2 port and offers better compatibility (more games supported) than previous versions.

If you're new to the whole emulation scene, MAME stands for Multiple Arcade Machine Emulator. Designed to emulate the hardware of arcade games, it was first publicly released on February 5, 1997 by Nicola Salmoria and the rest of the MAME team with an open-source license.

Installation isn't very complicated, but you will need GCC 4.0.2: DevKitGP2X rc2 to compile the code or a slightly modified version of GCC 4.1.0 (DevKitARM r18) linked with GCC 4.0.2 (DevKitGP2X rc2). Before doing anything go over the Read Me document included in the compressed file to avoid potentially damaging your PSPs.

Thanks to Francisco Vergara for the tip!

Download: MAME gp2x 4.6
Download: MAME gp2x 4.7

There's a new release of devkitPro Updater for you guys, which should make the process of selectively downloading the devkitPro team's toolchains and programming tools a lot easier and, hopefully, more bug-free.

The app lets you download the latest versions of their different toolchains for the PSP and DS, as well as some other DKP releases. Best of all, you're free to pick and choose what you need, so PSP users won't have to go downloading all 170-something MB if they want to try devkitPSP 9, and neither will DS users when they want to grab devkitARM.

As the devkitPro team state on their website:

devkitPro Updater 1.4.2 has been rebuilt with the latest NSIS 2.23 and a more recent version of the inetc plugin used for downloading files. This should be more stable and hopefully remove the installer crashes some people have been experiencing.

That being said, it's an easy-to-use interface, and veterans who've been using their toolchains shouldn't have any problems getting the latest updates through it. Enjoy!

Download: [devkitPro Updater v1.4.2]