For a personal project (and the purpose of learning some AI) I was thinking of creating some sort of "AI Mod" for Half Life 2. I am thinking about using a top down camera, Combine Vs Rebels and rewriting their AI so you can start them of in a map and then they'll move, behave, take cover, attack how squads do in the real world. Like storming houses, flanking, setting up strong points, guarding etc. but with the AI deciding what to do when. What would be te best way to implement this? Is it feisable (sp?) to do this? Thanks.

Yeah, it would probably be very cool too, but a little meaningless. Maybe it could eventually turn into an RTS-game though. XD

Anyway, I think you could start with writing AI for a soldier on his own. (Deathmatch) and then move on to squad-based AI (having a leader, covering eachother) and then maybe something on a higher level like multiple squads cooperating (alpha bravo, stealth vs firesquads) or intelligent environment adaption (retreating, walking around).