The Creative Cow has some great articles by industry leaders
Creative COW Business Articles
Check out the multi part article by Walter Biscardi, very good.
For me it was easy, people found me, I wasn't looking for work.
Post samples of your work for people to see, post in forums like this, get the word out.
Mostly you will need examples of what you can do, a video portfolio so to speak.
Even if these are just slideshows to start with, show some creativity and do some things that are out of the ordinary.
There are some great examples in the Gallery at muvipix.com
Check out the 2005, 2006 and 2007 contest videos to start with, especially the winners.
They will give you some ideas to work with and show you some things that will make a video unique and fresh.