Steve Clift at Do-Wire has set up a wiki link list for all the internet responses to the London bombings - especially first person accounts and images. Please update the page if you know of any other good blogs or websites, and check back again soon.
http://dowire.org/wiki/London_responds
There's also this new page on Wikipedia explaining the events of the day. Watch it morph throughout the week as more evindence turns up.
http://en.wikipedia.org/wiki/2005_London_transport_explosions
