Silvia,

All over the world. Too many to list. Do an internet search with 
google and you'll spend days digging out from under all of the sites. 
Personal pages, university labs, commercial sites with excellent 
reference material ....
Here are 3:
Tips & Tricks of Microscopy
http://www.biotech.ufl.edu/~emcl/tips.html
MicroAngela
http://www.pbrc.hawaii.edu/bemf/microangela/
Microscopy Society of America
http://www.microscopy.com/

The MSA site links to many others and also has the link to subscribe 
to the microscopy listserver, which, inter alia, covers EM 
extensively.
And, since you live in the UK, why not check the Royal Microscopical 
Society site?

Phil

>Does anyone know if there are some useful web sites about EM (electron
>microscopy)? Is there a chat about EM?
>
>Thanks in advance
>Silvia

-- 
Philip Oshel
Supervisor, BBPIC microscopy facility
Department of Animal Sciences
University of Wisconsin
1675 Observatory Drive
Madison,  WI  53706 - 1284
voice: (608) 263-4162
fax: (608) 262-5157 (dept. fax)