As far as I'm aware, Apple have not announced this yet. You almost certainly know that they go on sale in Apple stores in the UK (March 25th). If you go to the Apple UK web site you can sign up to be sent 'further information' by email.
Also, you can 'pre-order', in the iBooks store, the Apple iPad2 manual (iOS 4.3), which will become available March 11th. It's free....
I've seen rumours - OK, should never rely on these - that the actual sales of the iPad 2 won't start until 5pm on March 25th - but I'm not sure that I'd place any credibility on those - just thought I'd mention it in case you plan to queue....
Tim
Scotland