AddressX for Mac

From Snerdware:

AddressX will bring the contacts from your company's Global Address List (GAL) directly into your OS X Address Book. What does that mean for you? It means that your Exchange GAL contacts will look and act just like the other contacts already in your Address Book. Search them, export them as vCards, sync them to your cell phone and take them with you. Take full advantage of the new system-wide address book instantly. Use your Exchange contacts seamlessly from applications like Mail, iCal, and many others.

AddressX is 100% transparent to both OS X and Exchange. As long as you have an Exchange server 2000 or 2003 with WebDAV enabled you are ready to go. No additional software needs to be installed on Exchange and no changes are needed for Active Directory. Best of all, if you can access your Exchange server on the Internet you can use AddressX from any machine with an Internet connection.

This trial version of AddressX will only download the first 25 contacts found in the Global Address List (GAL) of your Exchange server. The full version of AddressX will download all the contacts in your Global Address List.