SmallNews source code is available at smallnews.googlecode.com. This is currently read-only. If you are particularly keen to contribute changes, let me know (by clicking the Feedback button on the left), and I could look at changing that.
To get the latest code, use a Subversion client and follow the instructions here. There is also a releases branch in the repository to get the code for a particular release (starting from 2.0b3).