Confidential to American expats living in London and elsewhere in the United Kingdom:  Here are a few resources I've compiled for where you can buy American "stuff" in Britain.  But be forewarned that your U.S. urges for home will cost you a pretty pound.  A box of Twinkies will sell for about $12, and a box of Lucky Charms costs almost $18!

American shopping

American Soda Company
http://www.americansoda.co.uk

Cybercandy
http://www.cybercandy.co.uk
11 Shelton St., Covent Garden

Let's Eat Direct
http://www.letseatdirect.com/

The Overseas Buyers Club
http://obcusa.co.uk/shop/home.php

Panzer's UK
http://www.panzers.co.uk/

Partridges
http://www.partridges.co.uk/

Rosslyn Deli
http://www.delirosslyn.co.uk/
Our personal favorite, located in London's beautiful Hampstead neighborhood.

Selfridges
http://www.selfridges.com/
The food hall of London's mega department store has a small "Cult Foods" section where you will find some American products

Where to meet Americans

The London Expat Meeting Group
http://american.meetup.com/11/

UK-Yankee
http://www.uk-yankee.com/
(IMHO, the #1 expat advice and meetup site)

The American Hour
http://www.theamericanhour.com/

American dining guide

Bodeans
http://bodeansbbq.com/
Great southern barbecue; plastma TVs show American sports. Three London locations.
* 10 Poland Street, London, W1F 8PZ Tel (020) 7287 7575
* 169 Clapham High Street, London, SW4 7SS.  020 7622 4248
* 4 Broadway Chambers, Fulham Broadway, London, SW6 1EP 020 7610 04440

Ed's Easy Diner
http://www.edseasydiner.co.uk/
Five locations throughout London

Fatboys Diner
http://www.fatboysdiner.co.uk/
Location: Trinity Bouy Warf, 64 Orchard Place, London. E14 OJW.
DLR station: East India

Texas Embassy Cantina
http://www.texasembassy.com/
1 Cockspur Street, Trafalgar Square

Tinseltown
http://www.tinseltown.co.uk/
* 44-46 St John St, EC1M 4DF. 020 7689 2424 (open 24 hours)
* 104 Heath Street, NW3 1DR. 020 7435 2396