most cruises include flights, though ships based in America may not. And cruises have never been cheaper, so if you have time, go for it; the lines are discounting heavily because of the credit crunch. In general you pay extra for drinks and excursions, and sometimes tips. I've been on Ocean Village and loved it
http://www.oceanvillageholidays.co.uk/
There are quite a few others. Look in the travel pages of the Saturday and Sunday papers for the best deals.
Never pay the brochure price - aim at about half of it. Lots of specialist websites like 1st4cruising and cruise.co.uk have discounts too.