Hey, one method I have used successfully is a plugin for Virtualdub called MSU Deflicker. If you haven't heard of/used Virtualdub before, it is a free video processor for windows. As a processor, it doesn't have a lot of editing abilities, but there are a lot of plugins (which are very easy to install into Virtualdub thankfully) you can download from around the internet that will do interesting and useful stuff to your footage.
You can try out the MSU Deflicker from here: VirtualDub MSU Deflicker filter. They also have a bunch of other filter plugins you can get free also. The one thing about it, is that it is relatively automatic. This can be good or bad. If it works first time, it can really help get rid of light flicker quickly and easily and the results can look great. On the other hand, if it doesn't work first time, you're probably not going to be able to use it given how little you can tweak it. Either way, it might be worth a try. I've had both really good results and completely useless results from it.
That might help.