Like many professionals and ubergeeks :) I have 2 exchange accounts, Personal and professional. Using outlook and activesync/WMDC I can sync my calendar/contacts/etc. However, once I configured direct exchange sync (for mobile wireless sync) I lost the ability to sync contacts and calendar and tasks to the second exchange server.
Then I found
myFunambol
Which provides a client for outlook (and thunderbird and such) which will sync to their server. They have a WM and iPhone client which will connect your device to their server for syncing.
I installed their Outlook Client on my work and home machines and scheduled 2 way sync on each. With my device already configured to use exchange OTA sync on my personal account, I now have OTA access to synced work and personal exchange accounts.
email access is provided by
Seven, which will provide OTA push email from multiple sources