United has a program called United College Plus which provides Mileage Plus bonuses for graduation, community service, and other activities. There is an associated College Plus Visa offered by BankOne (First USA). Chase offers a Platinum Mastercard for Students, which offers travel vouchers on Continental as well as a rewards program.

There may be other programs out there. Back in the day, AA and NW offered student voucher programs, and CO's partnership was with American Express.

As far as holiday travel, etc. I don't have much generic advice. Dallas is a much bigger city than Ithaca, NY so I imagine you won't have to make commencement hotel reservations four years in advance and dinner reservations one year in advance like I did.