Sync’Em syncs Microsoft Exchange, Google, Apple contacts and

Derman Enterprises has released Sync’Em 1.0 (http://www.syncem.com),
a new sync hub for Macs. It’s compatible with Mac OS X 10.4 and
higher and costs US$39.95 for a single user license.

With Sync’Em, you can sync your Exchange, Google and/or Address Book
contacts and sync your Exchange and/or Google contacts across
multiple Exchange and/or Google accounts. Soon you’ll be able to sync
your Exchange, Google and/or iCal calendar events/tasks and sync your
Exchange and/or Google calendar events/tasks across multiple Exchange
and/or Google accounts.

You can do this without installing software on your Exchange server.
A demo is available for download.