I recently attended one of the O2 Technology roadshows and I'd definately recommend them for anyone interested in mobile email, or remote working. They provide a good overview of what's in the market, and also a chance to meet the suppliers - including RIM, Microsoft, Palm, Motorola Good, Destiny Wireless, and a couple of others.
The next ones are at:
Five Lakes Hotel, Colchester 8 April
Twickenham Stadium, London 9 April
The Russell Hotel, London 11 April
You can register online at:
http://www.o2events.com/technology/