Subversion:
Subversion is an open source version control system.
http://subversion.apache.org/

SharpSvn:
SharpSvn is a binding of the Subversion Client API for .Net 2.0 applications.
http://sharpsvn.open.collab.net/

Version Control with Subversion:
Online home of Version Control with Subversion, a free book about Subversion.
http://svnbook.red-bean.com/