I usually make my own, because the people who put them online do not often include the specifics that they want their students to look for. It is a good place to start, though, and even though it is the only webquest site I have ever used, I do like the setup in terms of the way the students see things. It is not hugely convient to use, and you can not use the same site over and over even if you are looking at different info on different pages.
If you want to look at mine feel free. I include every question that I want my students to look up in the webquest (it is over the page they are supposed to be looking at, and if you can't see it just "pull" it down), and I give my students a handout with the same information because even though it is on the page it is not convient to see.
Best of luck, and I hope you are able to share what you learn in your class.