KiCad is a great EDA (Electronic Design Aid) which is used in the valvers.com open hardware projects. It is open source and so can benefit from users getting stuck in to solve their own problems and improve the application to suit their needs.
There are several sources of information regarding using KiCad. For a start, there is the documentation (pdf help files) that come with KiCad. Each program (EESCHEMA, PCBNEW, etc) has it’s own help file PDF which is well written and covers most aspects of the program.
There are a few places on the web to pick up some hints and tips from too:
There is also an active mailing list for users.