See this for selecting repositories in Ubuntu:
http://www.psychocats.net/ubuntu/sources
If you are new to Ubuntu / linux, you should read through that whole site. It is a great resource for getting started with Ubuntu.
Stay away from those ppa repos until you get some experience with Ubuntu. Those ppa repos vary greatly in quality. Many are fine; but some people have developed dependency problems and other endless grief while using the ppa repos. I have never used them; and I don't have problems.
Also, you can steal the free Ubuntu Manual from here:
http://ubuntu-manual.org/
And welcome to the LQ forums! Welcome to the cool side of computing!
