Teleo Brings SIP to the Desktop – Skype One-Upped by Teleo
"A software telephone on the laptop ties into your Microsoft software making it a one-click operation to call anyone listed in your laptop. Highlight the name of an e-mail sender who’s in your address book, click to call, and hear that person’s phone ring. See a phone number on a Web site in IE? Click and call. Calls to other Teleo users are encrypted like Skype calls.

The phone number assigned to your laptop accepts incoming calls from any other telephone, something Skype has yet to introduce (their SkypeIn service is still in test mode). When your laptop is off, forward the calls to your cell phone. No modern road warrior/expense account white collar wage slave is without one of the two every hour of the day and night."

Unlike Skype, Teleo is using SIP to power their system. It would be neat if you could route the line to an Asterisk PBX .  Of course, the technology behind this is pretty straight forward and open to anyone if your handy with Linux:)