Londonist has minute by minute coverage of the suspected terrorist blasts in London today. Included in their bird's eye view of the event is a link to the incredibly comprehensive (and constantly updated) wikipedia entry about the transport explosions.
Update: Locally, we moved to modified tactical alert and a heightened alert at LAX but not for any specific threat.
Update II: For even more minute by minute coverage, check out europhobia. From bloggers in SoCal, Boi From Troy thinks aloud (a-text?) about how snarky blogs can write about terrorism; LAFD points to homeland security's tips on readiness (including what to do in case of an explosion) and West LA Online has similar thoughts but points at the Red Cross Preparedness pages instead.