In the meantime, here's a great video I found explaining a big part of the crisis and how it's connected to bad mortgages. There's a lot of really interesting stuff in this video, and it helps you understand how so many banks and investors can be suddenly find themselves on the verge of collapse when people stop paying back the bad loans they gave. A big thanks to Joey deVilla for linking to it.
The Crisis of Credit Visualized from Jonathan Jarvis on Vimeo.