Jabber for the Mac
Cisco’s Jabber for the Mac successfully integrates the Macintosh with Cisco’s phone systems. Jabber can be used to control your Cisco desktop phone or act as a soft phone. It provides access to your Address Book as well as your Cisco UM directory. Click here to read the review.
Jabber integrates phone, chat, voicemail and other functions. While there are some shortcomings, I had some troubles at times with the contact search function, in less than a week some of our staff are using their Macs with Jabber and iPhone earbuds instead of their phones to make and place calls. Even if you aren't interested in using Jabber as a software it is the best way to listen to voicemail messages and place calls.
As of UM 9.0, the Jabber client is included with the standard license, so trying it out is a no brainer. Jabber only works with the Cisco UM phone system.