MaLa is basically front-end (wrapper) software designed for Windows-based emulator cabinets. It's basically a step up from running MAME32 / MAMEUI. There are heaps of other front-ends too, but after trying a few I got a nice vibe from MaLa so I stuck with that.
You configure it by telling it where on your disks to find MAME and associated files (or any other emulator, any executable, batch or whathaveyou), and it gives you a nice menu system to navigate the available games without needing any keyboard/mice.
It comes with a layout editor to build your own skin (which I chose to do for my cab) or you can download one to drop in.
It's quite configurable but can take a while to get the game list(s), navigation key/button mappings and stuff all schmicko. Definitely set it up on a normal PC first and then copy everything over to the cab
Here's a video of some dude's MAME cab booting straight into MaLa - although he's gone to a lot of trouble, he's missed a simple setting to hide the little CMD window (visible for a moment at 1:26 seconds in). Oh, and he's got an ugly layout.