I use movie maker for my wee surf movies – its very easy to get your head round. Unfortunately it tends to a) be quite buggy/crash easily if you are using a lot of very big files in my experience (save your project often) b) doesent allow for high quality output – it forces you to use one of a variety of compression techniques none of which seem to enable high quality digital output (other people may have found a way round this I guess.)
I plan to get pinnacle myself at some point – but will pay for it… thus subsidising the R+D which you piratical types get to take advantage of 😀