I'm planning on taking a 4 month trip around the world and was looking at getting a RTW ticket (start in D.C. and then head West), but I don't really want to be stuck along the way with departure dates that are set in stone.

Does anybody know of any flexible RTW tickets? If I get a business class ticket can I change the dates w/out incurring any fees?
Is there a better way to do this??

Thanks for any help!