Authors CurseForge

Here is a list of links to sites with resourceful use info on SVN, Git, and Mercurial (hg). If I've missed a site you find to be helpful in learning about these specific version control systems, please post the link and I'll try to keep this first post updated. :)

SVN
TortoiseSVN FAQ: http://tortoisesvn.tigris.org/faq.html
TortoiseSVN more info: http://tortoisesvn.net/


Git
Git - SVN Crash Course: http://git.or.cz/course/svn.html
Git Cheat Sheet: http://github.com/guides/git-cheat-sheet


Mercurial (hg)
Wiki page: http://www.selenic.com/mercurial/wiki/

There's a lot for git, I'd suggest the github guides in general:
http://learn.github.com
http://gitready.com
http://git-scm.com