If you can eeek the key back just a hair and have the shift lock release work, the problem is the ignition switch. This is the problem about 20% of the time. More often than not, about 78% of the time, the problem is the microswitch. The remaining 2% would be the brake light switch. If you have brake lights, there is an easier way to check for a problem with the brake light switch in regard to the secondary signal for shift lock release. Simply check for any codes in A3. If you aren't worried about having shift lock, and aren't worried about liability or some type of state inspection, you can just pull the cover on the passenger side of the tunnel, and bend the little armature up and out of the way.

Hope this helps,
Chris