A/T vs 5 spd

As stated in the previous post, (Idle RPM too high) my wife has a 92 conv, 5 spd. I just inherited my daughters 93 conv, 3 spd A/T. After driving the 93 a few times, I realize I hate the A/T. Can anyone give me an idea how hard/simple it is to swap the A/T with a manual 5 spd. I'm not a mechanic, but do work on the Geo's. Was just wondering if the swap would be worth the effort. Any opinions?