It depends on how fast you want your stuff, too. You can check out companies like upackweship which will put your stuff on a boat and it usually takes 2-3 months, you can pay the excess baggage fee to take it all on the plane with you, you can cruise over on the Queen Mary 2 (with no baggage limit), you can mail/fedex/ups stuff...there are loads of possibilities.
Are you planning on taking absolutely everything with you or do you have room to consolidate? Do you have housewares/fragile items or is it mostly books?
If you've got a lot of books, you might want to look into M-Bags through USPS. We discuss it at length here:
http://talk.uk-yankee.com/index.php?topic=53427.0 There's some great advice about packing into suitcases here:
http://talk.uk-yankee.com/index.php?topic=53409.0People also completely forgo suitcases all together and just pack into rough totes for the flight, as long as the rough totes fit the airline size limits.
And if you can, try to take extra clothing over on visits and leave it, so you'll have more room in your suitcases for other things when it's time to move!