OK, I've settled in a bit here in the UK, so I'm sending off my first dispatch:
1) British pubs are notably different than US bars in terms of how devoted the patrons are to conversation. At 5PM in a London pub, the volume of noise produced by the multitude of conversations occurring is startling to anyone accustomed to US bars.
2) Marlboro Lights here have brown filters: What's up with that?
3) The way I cope with crossing British roads -- where they drive on the wrong side -- is by frantically swinging my head back and forth in both directions.
More to come.