I used wufoo.com for the first time this week. It allows you to create a quick survey and post that survey on any website. I used it to allow people to signup for a team in Sunday school (the teams will organize various aspects of the class).
It worked really well and was simple. Go to http://hutchinsonfamily.googlepages.com/home to see it in action. The form is at the bottom, and it took me all of 5 minutes to setup. I can access the information as an excel export or in the wufoo gui.
But of course, as a tester, I must point out a bug I found. A phone number of 234-555-6789 displays as 234-55567-6789. I love web 2.0, but the "no testing" and "perpetual beta" aspects will start to drive me crazy at some point. Software must work to be useful. End of story.