Useful Links
Google Groups for Revit Python Shell: a question and answer forum.
https://groups.google.com/forum/#!forum/revitpythonshell
Revit Python Shell Discussions at Stackoverflow: a question and answer forum.
http://stackoverflow.com/questions/tagged/revitpythonshell
AUGI Revit API Forum: a question and answer forum.
http://forums.augi.com/forumdisplay.php?218-Revit-API
Autodesk Revit API Forum: a question and answer forum.
http://forums.autodesk.com/t5/revit-api/bd-p/160
Nathans Revit API Notebook: some great examples for Revit Python Shell.
http://wiki.theprovingground.org/revit-api
The building coder: a blog with various Revit API topics.
http://thebuildingcoder.typepad.com/
Autodesk Developers Network:
http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=2484975
Here you can go through the "My First Revit Plug-in" tutorial, download the Software Developers Kit, or watch the DevTV videos.
BipChecker: a useful (maybe necessary) Revit add-in.
https://github.com/jeremytammik/BipChecker
Revit Lookup: another useful Revit add-in.
https://github.com/jeremytammik/RevitLookup/releases
Scripting with Revit Python Shell and Autodesk Vasari. A very helpful word document with info for using the Revit Python Shell.