As far as i know Jordan is right, EV 9 will be released in 3rd quarter of year 2010 and by that time Exchange 2010 sp1 will be available in the market and EV 9 will be supporting Exch 2010 SP1 onwards..
Out of interest has anyone tried archiving from Exchange 2003/2007 in EV 8.0 and then moving the mailboxes to Exchange 2010, although stopping archiving before the mailboxes reach the 2010 server. In theory the archived items should be accessible, although not had time to try it out.
There are lots of eager beavers looking at Exchange 2010 being held up by the unsupported issue, although I guess this is also pretty much unsupported until EV 9.0.
Whilst I am thinking out loud, can anyone explain why EV 8.0 and by the look of it EV 9.0 is not supported on Windows 2008 32 bit even though it is supported on Windows 2008 64 bit in 32 bit emulation mode?