There is no such thing as "Exchange" support. The android just needs to support email clients that can use HTTP(s), IMAP, &/or LDAP based connections to their email servers , which I bet it already does... or will soon. The difference is that your average exchange user isn't going to understand what that means... or how to configure it. So the learning curve is likely a bit higher.
But whatever...
I'm still p/o'd that T-Mobile lied to me about arrival time when I purchased my G1.