[Python-Dev] Primer on distributed revision control?

[skip at pobox.com]

With all these distributed revision control systems now available (bzr, hg,
darcs, svk, many more), I find I need an introduction to the concepts and
advantages of repository distribution.  It seems to me that it has the
potential for leading to anarchy, though I can see how some things would be
improved (working offline, maintaining local patches).  It's not obvious how
I push changes back upstream.  Can someone point me to some useful content
(web pages or books) which will help me wrap my brain around the ideas?
Maybe a compare/contrast of the major players?

Thanks,

Skip