An update will be available on the Palm Pre to support the new Exchange 2010features (e.g. presence awareness, IM, sms, email, exchange voicemail using mp3 etc). Exchange 2010 also supports any browser running webkit.

I don't know when the update will be available on the Pre but I get the impression it will be by the end of this year. Exchange 2010 is due for release before the end of this year.