Outlook Team blogged about a new feature of Outlook 2010 which is to use multiple accounts from a single profile..
For everyone using the Outlook 2010 Technical Preview, there are a number of improvements for working with multiple Exchange accounts. My name is Andrew Sullivan, I'm a Program Manager working on Outlook and it's my pleasure to highlight some of these improvements.
Connect to more than one Microsoft Exchange account simultaneously. If you've worked with more than one Exchange account in Outlook 2007 or earlier, you may have resorted to using multiple Outlook profiles to access your additional accounts. No more, as Outlook 2010 supports connecting to as many as three Exchange accounts from a single profile.