And, of course, there is also software you can buy, with various levels of features, depending on how much you want to pay. However, if all you want to do is string videos together and add audio, there's no reason to pay for it.
Also, I don't know about Mac software, I don't have a Mac.
I've always liked working with Video Studio by ulead. (although I think it has a new name now.) It allows you to string videos still images, etc and you can add a soundtrack and a separate audio track.
But also I find it handy because you can trim video if you find a given shot is going to long.
The OP has been banned, so I think it's safe to say there's no need to continue answering this thread. Maybe one of the mods should lock it (just a suggestion.)
Posts
For Windows:
http://explore.live.com/windows-live-movie-maker
http://download.cnet.com/windows/video-editing-software/
For Linux:
http://www.openshotvideo.com/
http://www.pitivi.org/
http://www.kdenlive.org/
And, of course, there is also software you can buy, with various levels of features, depending on how much you want to pay. However, if all you want to do is string videos together and add audio, there's no reason to pay for it.
Also, I don't know about Mac software, I don't have a Mac.
But also I find it handy because you can trim video if you find a given shot is going to long.