Hey Jennifer,

If you're using Adwords you can also use their free "website optimizer" tool from inside your Adwords account.

I use this a lot myself (even for sites I don't promote with PPC) and you have the option of running A/B split tests or more complex multi-variate split tests.

Google make it really easy to see what's going on and analzye the results so you don't need to be a statistical whiz to figure it out ... "green" means it performs better, "red" means it performs worse

Hope this helps,

Richard