Client Access Server Role
The Client Access role on Exchange 2007 is responsible for remote access to the server - so includes OWA, Outlook Anywhere and Exchange ActiveSync.
Where * appears after the article, it is in the Exchange 2010 section, but the same process applies to Exchange 2007.
Client Access Role
Enable Outlook Anywhere *
Reinstall the RPC Proxy Component on SBS 2008
Change Expired Password in OWA
Making the OWA Login Page the Default Page on a Web Site
Troubleshoot the Autodiscover Service *
Exchange ActiveSync
Exchange ActiveSync Setup for Exchange 2007
Troubleshooting Exchange ActiveSync