Windows Movie Maker is pretty simple and free. You can cut the video how you want it, add in multiple clips, and add in music to a video.

Get GoPro Studio free from the website.

Cyberlink PowerDirector 12. Less than 100 bucks. Easy to use. Has plenty of options should you want to make more complex videos in the future. Lots of youtube videos that show how to use it. I was able to make multicam videos very easy.

Simple, just get Gopro studio off their website. Easy to use and it walks you through the process first time. Allows you to cut down parts of your video. You can just start recording it in the pits and when you get out on the track you can start the footage from there.  Make sure you copy the files off your camera and onto your hard drive first. I haven’t played around with adding music or captions though.

Here is a video I made two days ago with GoPro Studio, it is somewhat lacking in some ways regarding pro editing capability, but for a casual user it rocks, plus you can have some real fun with it as you can see in my video…

http://youtu.be/wXZaLov5QhM