Here's what I did:
1) On my work PC I set up MobileMe in the control panel to sync my contacts with the Windows Address Book
2) After they were synced I went to the Windows Address Book and did File > Export > WAB
3) I opened Outlook (which is running on my works Exchange server) and in Contacts I went to File > Import & Export > Import Internet Mail and Addresses > Outlook Express > Select the file from wherever you saved it (from step 2)
That worked for me! The BES took all the contacts and now they are showing up on my BlackBerry as well
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