If you want to have a play with Ex2010 SP1 without installing into a test environment then you can download a pre-configured VHD from here:

http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=53f7382a-3664-4de3-8303-31e514d69f02

Where you can evaluate SP1 for 60 days.

Useful.