Londoners - everyone who lives in London, I mean - will not let this stop them going about their normal business. In the 80s and early 90s we had occasional IRA bombs - usually, of course, there were warnings with those, but not always. There was a period I lived outside London but worked in London, and I can remember arriving in Victoria, getting to the office then finding an IRA bomb had gone off shortly after where I had been, which prompted calls from friends.
Norm has a good summary of the news. The Guardian is carrying people's accounts. The BBC has eyewitness accounts, and a reporters' log.
Jo Salmon has a round-up of the international coverage.