Handbrake is designed to do one thing very well - to transcode non-encrypted DVDs to a file ready for Internet sharing.
Handbrake has a very easy to use interface, and the default settings normally work very well. This has meant it has become very popular with Mac OSX users (the original platform that Handbrake was made available on)
Above you see a screenshot of the main screen of Handbrake. The software works on Mac OSX, Windows and Linux.