If you are employed, check with your personnel/HR dept;
If you're a student, check with your careers adviser;
Try the local library (even better if you have a local College/University library)

What does Google say?

Specialist training company: http://www.feabhas.com/
"Feabhas specialise in training courses for real-time embedded developers"

Possibly Doulos (definitely ARM, nothing specifically 8051):
http://www.doulos.com/content/t...ourses.php

You should also check out all the distributor websites, as they often have courses/seminars relevant to their product lines.
In particular, try
Nohau
IAR
Hitex (Keil distributor)

http://www.computer-solutions.co.uk/

Also check out University websites - they often run public short courses.