I've just started to take a look on how to editing videos and was searching the net to find some tools for Linux.
After trying a couple I found out about the KDE application Kdenlive from some blog post and I must say that this tools looks very promising. It did crash once when I tried it out but I can live with that since I'm not a heavy user of video editing. I just need something for creating youtube videos occasionally.
In addition to the great app there's also a bunch of video tutorials here to help you getting started.
So if you're in the same position as me I think you should take a look at Kdenlive