For a concise summary of the Transitions movement (all links open in new window), see this from Rob Hopkins: http://www.transitionnetwork.org/support/what-transition-initiative
For an ‘independent’ take see Wikipedia: http://en.wikipedia.org/wiki/Transition_Towns
For a ‘deeper’ discussion of Transition principles (the ‘politics’ if you like) in terms of transition principles, ‘inner’ and outer transition, permaculture principles and resilience see this from transitionnetwork:
For the film ‘In Transition 1.o’ (49 minutes online and to purchase) see here: http://transitionculture.org/in-transition/
For the Transition Primer (51 page pdf version 3 of the much longer Transition Handbook – itself in revision) see first here:
For more on ‘Energy Descent Action Plans’ (EDAP) see this from Totnes: http://totnesedap.org.uk/
For a handy presentation of Chris Martensen’s UK Crash course on Peak Oil (and Peak everything and the credit crisis) see this from Bolton: http://www.transitionlinks.org/?page_id=772 (scroll down their page!)
For everything else, follow the links on the sites above and this website.