Turning an Auto into an Auto-Manual?

Alright i have a question: 1987 GTA Trans Ams only came in auto transmissions but my question is...could it be turned into a auto-manual like they have in the newer "sport cars" such as Eclipses, Tiburon's, etc. easily? A friend told me i should look into it and im thinking that would be kinda cool, but i don't wanna go all out and get a manual put in if its as expensive as i hear it is. So please lemme know what you think? Thanks