Alright. First off, make sure you enjoy and are passable at math and physics. If you struggle with these, you will struggle with just about all engineering. Additionally, are you detail oriented? Engineering is one of those fields where you can do the first 75-90% in your garage - the reason you get paid are the little details.
After that, "prerequisites" should mainly be High school. If you have some college under your belt, you'll get to start into the core engineering classes a little sooner, possibly - it depends on the school.
As for schools to look at, it depends on what kind of aerospace you're looking into and how much you're willing to spend. Typical top of the list type schools are those such as MIT, Stanford, Georgia Tech, Purdue, Embry-Riddle, Cal-Tech, etc. These are NOT the only good programs, but are consistently in the top 20, usually top 10.
Shameless plug for the school I attend - Wichita State University has the 2nd highest research dollars in the nation for aerospace engineering. We are partnered with the National Institute for Aviation Research, which is located partially on campus. There are research opportunities in everything from aerodynamics to structures.
Really, it depends on what you want to do. Feel free to contact the different schools and talk to students or professors. Visit any schools you can to try to get a feel for the campus and see if you could be happy there for 4-10 years (depending on if you want to go for advanced degrees or not).
I hope this helps. Feel free to ask me any other questions if you need advice.