CuPhone Personal Phone Gateway (PPG)
Basically, this device connects to your PC (via USB) as well as a PSTN wall socket. Then you enter in a pre-specified PSTN phone number, such as a cell phone number into the CuPhone Personal Phone Gateway (PPG). Then, you can be on the road and calls to your Skype number will be forwarded to your cell phone! COOL STUFF! It can even detect when your phone line is in use as to not interfere. They also have another device called the USB to RJ11 Phone adaptor that allows you to place outbound Skype calls with any regular phone (including cordless phones). You can place/receive/hang-up Skype calls without using your computer's keyboard or mouse which is a cool feature.
Andy Abramson points out that you can connect the Personal Phone Gateway (PPG) to Vonage, Packet8, CallVantage, etc. via your ATA's analog port. Andy - "In theory, I could load the software on my PC, connect via IP from anywhere to the PPG which is connected to the telephone adapter of say CallVantage or Vonage or Packet8. all of whom have unlimited calling capabilities and dial out as much as I want to, then share the software with family and friends who are connected by IP to the net and let them call too and reach whomever they want, giving them unlimited and free outbound calling."
Good point Andy. Well said.
Check out their home page: CuPhone Internet Telephony solutions