Hg Init: a Mercurial tutorial by Joel Spolsky

"Mercurial is a modern, open source, distributed version control system, and a compelling upgrade from older systems like Subversion. In this user-friendly, six-part tutorial, Joel Spolsky teaches you the key concepts."

Git Immersion

"Git is a powerful, sophisticated system for distributed version control. Gaining an understanding of its features opens to developers a new and liberating approach to source code management. The surest path to mastering Git is to immerse oneself in its utilities and operations, to experience it first-hand.

Git Immersion is a guided tour that walks through the fundamentals of Git, inspired by the premise that to know a thing is to do it."