Hi. Another cruiser who posts here REDZONE. Just renewed his vows on his last cruise. I'm sure he would be able to answer all of your questions.
Life is too short to let the ship of your dreams sail without you.
Carnival Destiny Feb. 2006
Carnival Fascination Feb. 2007
Royal Caribbean Grandeur of the Seas Feb. 2008 The DTW & MsBJ tour
Carnival Valor MsBJ and Dina Feb. 2009
Carnival Glory MsBJ and Dina Feb. 2010
Carnival Dream MsBJ and Dina Feb. 2011
One of my co-workers got married aboard the Caribbean Princess. It was really nice, and I think the wedding went off without a hitch. I'd guess the Carnival ships have a similar program, however, I don't remember quite as nice a chapel aboard them as aboard the CP.