If it's cranking, the battery is good enough. It's not the battery.
Check for spark at a plug or two (pull plug and while someone is cranking the car, ground the plug while it's connected to the wire, and I'd suggest pulling the fuel injector fuses so it doesn't flood). If that doesn't check out, look for spark at the coil.
For more things to check, look at the bottom of the following page under "Non DTC and Driveability Diagnosis", right side where it says "Cranks but will not run."
http://home.comcast.net/~fastbird/Tr...ech%20Aids.htm