Do I need a Visa for a 7 day trip from the UK to the US if I'm attending an IT training course?

UK pport holder travelling on the 05-03-11 returning 12-03-11 my pport expires on 6th Sep 2011 so I have 6 months remaining when I depart the UK I don't think this matters however I'm concerned that I may need a visa as I'm attending an IT course. BTW - I have an ESTA.