To confirm what the others have said, Apple will not cover the damage to your system under warranty. I don't know if you have any recourse with TSA, particularly since you couldn't report the problem right away. You can try their claims office, though:
http://www.tsa.gov/travelers/customer/claims/index.shtm
You'll find instructions and the appropriate forms there.
If they won't reimburse you for the damage, you'll have to look to homeowner's insurance or possible credit-card coverage. Or just live with the dent if the system is otherwise working properly and the dent hasn't affected any functionality (including battery removal).
Good luck.
BTW, if you have future questions about your MacBook Pro, you'll get the quickest and most accurate answers if you ask in the
MacBook Pro area. This forum is for the Mac Pro, Apple's minitower system.
Message was edited by: Dave Sawyer