Efi Source now sells a pre-wired megasquirt kit. If you want to do it yourself, here's the tutorial I wrote:

http://www.forabodiesonly.com/mopar/showthread.php?t=226125

-'02 Dodge Viper Ex-World Challenge racecar
-'73 Duster, 6.1 based 392 hilborn hemi, tko600, full floater rear 9", Hellwig custom bars, viper brakes, built for road course