What kind of food can I bring on a plane?

On Monday, I'm flying from Columbus, OH to Chicago, Il to Austin. I don't really have much extra money and I'm taking the trip to Austin to see my brother before he gets shipped to Iraq next month. (We've not seen each other in two years.) Also, I'm vegan (obviously), so I'm guessing I won't find much to begin with, even if I had time with my layover. (I'll have just enough time to grab my luggage if it's not being transferred and go to the next gate.)

I'm sure that there are restrictions on what I can and can't take, but I'm not finding anything on the American Airlines site. (I think that's the airline. My husband booked my ticket so I will have to ask him.) All I plan on taking are some nuts, dried fruit and maybe a peanut butter and jelly sandwich (or two) and some fruit and grain bars and granola bars. No meat and nothing overly funky. (Though some would say that my all natural PB and all-natural jelly on all-natural whole wheat bread is overly funky.) I might overpay for water and coffee at the air ports (unless the airlines still provide that in flight; It's been a couple of years since I have flown).

Also, I plan on taking my digital camera. Can I take that with me on the plane, or does it have to go in my suitcase? How many carry-ons am I allowed? (I plan on just taking my brief bag [messenger bag], but if I can take another, that would be good.)

Any information you can give me will be appreciated.