As Microsoft promised a couple of months back there would be a public beta of Service Pack 1 for Exchange 2010.

See: http://msexchangeteam.com/archive/2010/04/07/454533.aspx for the announcement.

Citing the link above we see that there are a couple of features interesting for us mobility guys:
- Tether-free Information Rights Management (IRM).
- Support for send-as.
- Notify on block/quarantine.
- Full implementation of conversation view.

In addition the admin will be able to administer Allow/Block/Quarantine in OWA/ECP.

There are of course other features not related to mobility too, but have one guess what I’m going to be looking into