Entourage 2004 (11.2 or later), Entourage 2008, and Entourage for Web Services all use the
OS X Sync Services to sync data with mobile devices. Here is
Apple's list of supported devices.
Depending on your server, you might not need to use Sync Services. If you're an Exchange user, then you can directly hook up devices that support Exchange ActiveSync to your server and everything automatically works. The iPhone supports Exchange ActiveSync, as do Windows Mobile phones like the BlackJack.
If you're not connecting to an Exchange server, and if you want to sync data with another mobile device (or if you want additional sync support beyond what's built into Sync Services), you can check out third-party sync products. I've heard good things about
The Missing Sync, which supports lots of devices like the iPhone, BlackBerry, and Windows Mobile phones. I've never used Missing Sync myself, so I can't tell you anything beyond hearing good things about it from others.
You might find it beneficial to post questions about syncing Entourage with various mobile devices to the
Entourage public forums, where lots of Entourage experts hang out.
Regards,
Nadyne.