Rater Control, Rating Control, or 5-Star Rating Control, call it what you like.
Here is a sneak peak at the Rater control in action: (Hint: use your mouse.)
Update: Sorry, the demo does not work on my new blog (WordPress), but the files are still available. :)
Note: For anyone who would like to link to my Rater control, please link to this post and not my demo page. Thanks. Also, I will make the C# source code for the .NET control available soon.