Here is some great info/sources if you are interested in getting started with cloth diapering:
The Diaper Pin
All About Cloth Diapers
Life More Simply
The Cloth Diaper Whisperer
There are a few to begin.
Here are some great links if you would like to start learning about how to start sewing your own stash of fluff!
Free Diaper Patterns
Goodness Gracious Free Diaper Pattern
Diaper Stash - A huge list of free patterns
This is just a small list of what is available for free out there on the web. If you spend enough time looking you can find some great stuff, all for free. There are also some great video tutorials on YouTube that will show you exactly how to make your own cloth diapers using items you might already have around your house.