Exchange 2007 provides mobile email support for more than just mobile devices... people often overlook the fact that you can use Outlook Web Access from a laptop or infact any web based PC anywhere!
Outlook Web Access (OWA) 2007 has been massively enhanced and is now very close to Outlook client in capabilities...
Prior to Exchange 2007 I'd use OWA only in emergencies... with OWA 2007 I actually used it for 2 weeks whilst my PC was in for repair with a broken hard drive!!
The document listed here outlines the capabilities in OWA 2007 compared to the Outlook 2007 client and Outlook 2003