there are quite a few threads on this topic if you search "jaw surgery". why is it you're not having treatment? have you seen an orthodontist? if not, i would ask your dentist to refer you. i was 1314 when i first had a visit to the orthodonist, but i was 16 before they started any treatment, and i'm 18 now and going to have surgery in a few months, so it'll all be over when i'm 19.
also if you search "orthognathic surgery" there are some groups on yahoo where people who've had treatment discuss it, so you might find some advice there as well. i still think the best person to ask would be a dentist/orthodontist.
and you said "which work" - the operation/brace combo should work if you've got an underbite. i don't think braces will be enough although there are people out there who've just had it sorted out with braces i think - not actually sure how that would work but there you go. hope this helps, feel free to pm or something if u want any info about my treatment etc
x