For a quick-fire, yet comprehesive explanation of the financial crisis and deeper systemic structural problems and why all of the 99% should be part of the anticapitalist movement for systemic change, I strongly recommend people spare 10 minutes and watch/listen to this lecture by David Harvey (with excellent accompanying snapshot annotation with cartoon illustration) which gives an excellent overview of the whole issue from a Marxist perspective:
 http://leninology.blogspot.com/2010/07/david-harvey-on-crisis.html

And of course there is, as you will probably be aware already, the film Inside Job (2010, directed by Charles H. Ferguson) which is highly recommended on understanding the 2008 financial crisis and the lead up to it, highlighting many of the crucial events that combined to take us to what happened in the fall of 2008 and today, including perhaps most crucially the repeal of provisions of the Glass–Steagall Act by the Gramm–Leach–Bliley Act in 1999 which effectively removed the separation that previously existed between investment banking which issued securities and commercial banks which held peoples'
deposits
Ref:  http://www.sonyclassics.com/insidejob/
(I strongly recommend you don't google a torrent for it)