If you need a free wireframe program, look no further. It is a Flash based online program that quickly gives you the ability to create a wireframe. The free account allows you to only work on one site. Once you are finished, you can have a wireframe that looks something like this (wireframe example created on mockflow.com).
Unfortunately, the mockflow site doesn’t offer any training on its product but I found this video review that is a great overview on how it works (and makes a nice tutorial on how to use it). The sound quality isn’t the greatest but it’s the best video I found. Please leave comments if you find better video links.
While mockflow isn’t the only wireframe tool out there (there are many), it sure works well.