Ayup. Been a while since I was a regular here, but I wrote the Tech Notes on that one. Can't find them now, though, so this will have to be from memory...
1) Find the ALDL connector under the edge of the dash, and jumper the upper right socket to the lower left to put the system into Learn mode. (A bent paper clip should suffice.)
2) The car should cycle its power locks off and on: *clunk* *clunk*
3) Now press any _one_ button on the new remote, just once. The car should acknowledge this with another *clunk* *clunk*
4) Repeat step 3 with any other remote you want to program, then remove the jumper, and you're done.
The car can remember a maximum of four remotes, after which the oldest-programmed one will roll out of memory whenever a new one is input. Good luck...
-- Andy Green