Hello Junior...
There are many reputable dive schools in N. America & around the world to choose from, but lets do a reality check first.
Dive school is big bucks. Programs range from 6 months at a trade school to two year assoc. of science degree college courses & range in cost from roughly $3500.00 (u.s.) to $12000.00 (these are guesstimates on my part...I've been out of dive school for 21 years...check around).
Commercial diving schools prepare you for work in two areas: inshore ( marine construction, salvage ) & offshore ( oilfield drilling/production/inspection/maintenance ). There is no "part time" work for newly minted deepsea divers fresh out of school; like many professions, the real learning/training is out in the field. A dive school ticket/degree is just to open the door. Be prepared to leave scuba behind, a working diver is a tethered diver in a band mask or helmet. Many schools are now offering courses in remotely operated vehicle (r.o.v.) operations/maintenance as these electronic marvels are doing more & more of the deeper work as system design advances.
As for Marine Archaeology, be prepared to go to school for a LONG TIME prior to doing any u/w digging. Texas A&M has a graduate program in Nautical Archaeology...Dr. George F. Bass used to run it though I'm unsure if he is still there.
Lifestyle. If you want to be a deepsea diver, you have to be prepared to do whatever is necessary to get work. I used to live with my bags packed & by the door, pager on. I could be called out to do a local day job or be sent several thousand miles away for weeks/months at a time. Don't even think of turning the job down...your name will go to the bottom of the call list, or they may not call again. When things get slow you have to scour the world for work & be prepared to go where it is & hustle it up. Your a hired gun & a good resume is your best ammunition. Wives? Girlfriends? I never found one that could handle the life, & many of my mates returned home to find notes on the door & their apartments cleaned out! Deepsea diving is not condusive to remaining in happy relationships. Having said that...for a single guy with no ties, theres no life like it. Adventure, travel, work hard/play hard, a girl in every port...all that good stuff. Gives you a few stories to tell later on. One more thing...deepsea diving is not for the "thin-skinned" individual; the ability to give & take shots is vital to your popularity & your career.
Bottom line: unless you are VERY SERIOUS about living "the life", don't waste your time & money.
Check out
http://www.offshorediver.com. This site is run by an active Gulf of Mexico oilfield diver & is an excellent resource for information. Click on "there I was" for some insight into the life of the working diver...I've penned a few there myself.
Regards,
D.S.D.