AIT is at Ft Sam Houston, bout 2 months long.
Besides Hawaii (Although I don't know why!!), you can be stationed pretty much anywhere in the world. Its one of the perks you get because this job is unique to the Army. You're a representative to all the services (even the air force when they need help!)
Depending on how you are as a soldier, promotion varys from soldier to soldier and command to command. Just don't get in trouble! I got E5 in a little under three years....
Any questions, all you gotta do is ask!