I've looked into this. If you want to get a position on a cruise ship as a musician, you must create a promo pack with Bio, Photos, and a Video of your public performance. You simply go to any of the major cruise lines websites and click on careers for example : http://www.carnivalentertainment.com/index.htm

It is not a glamorous lifestyle as you are part of the crew; you typically make $2500 month plus room and board. You typically share a room with someone and these are not staterooms, they are crew quarters. However, this may be the lifestyle for some people.

Good Luck.