Import and export is done with GEDCOMs.
See http://www.wikitree.com/wiki/GEDCOM_FAQ for instructions on uploading and some things to know before doing it.
P.S. From looking at your contributions http://www.wikitree.com/index.php?title=Special:Contributions&who=Porter-2929 it doesn't appear that you have already had a gedcom import processed. That doesn't mean you didn't upload one. If you think you might have, e-mail Tami at info@.