About 5 months ago I switched to Voice of IP technology for my phone service mainly for the lower costs. I can't complain as the service and clarity is close to a LAN line. I have found many cool third party applications that can take advantage of this technology. The first such product I can across was IBM's Domino Unified Communications (DUC). I found DUC so awesome that it motivated me to publish an article that I urge everyone to read called Integrating voice, email, and fax in a single unified messaging store.
Just the other day I noticed an article on lotus.com titled Lotus Notes- and IBM Workplace-based IP telephony rings up Lotus Award for Switzerland iscoord . This article integrates phone with Lotus Sametime. I know that would save me time. I don't want to spoil all of the features but leave it up to you to read the article for yourself.