I know carnival does have a link with all the info on submitting resumes for both on board and corporate:
http://www.carnival.com/CMS/Fun_Jobs...s_landing.aspx
But I have to say, after cruising last week, I could never see myself working on a cruise!! Too lazy, I am! These people work about 6 months straight, 7 days a week, 10 - 12 ish hours a day. and they are all so pleasant and hard working. We had thought it would be interesting to do that, maybe in your early 20s, right out of college, even, but.. wow. I will never complain about my 9 - 5, 5 day work week again! I can't imagine they pay much, either.

Which is a shame since these people work so hard!!
We did also notice that there were no american workers (for the most part) on the triumph. Interesting.
But good luck! You will travel to interesting places, though I'm not sure how much time you have to actually go on shore?