Yes most cruise companies do a wedding package at a cost,pick a destination then phone a cruise agent there are plenty with free phone numbers have a chat with them have some idea in your own mind of your spending limit?Best of luck.
Yes, theweddingexperience.com arrange it. Few ships allow you to get married by the Captain - Celebrity have now reregistered their ships to Malta so it is legal for the captain to marry you, otherwise you get married whilst docked in port or ashore.
We were married in May at sea on Sea Princess by the captain. We used theweddingexperience to arrange and organise everything- it was absolutely wonderful and I would recommend it. Call Princess cruises in the first instance and they direct you to theweddingexperience. P&O ships also do weddings at sea.