To use different Target URLs, create the AdGroups and get the terms in there, then create multiple ads with different Target URLs for the terms you want to do this for.
I will try the multiple ad groups with different target pages. I knew there had to be a way to split test landing pages :)
ecw02, you can also use multiple ads within one Ad Group to split test. Just give each creative (ad copy) its own Destination URL. Do make sure the Display URL (the one that shows in the ad) and the Destination URL (the actual address of the page the user goes to) are in the same domain though - so that the ads will be approvable.
AWA