Creative Labs produced a great device in the VOIP blaster. Unfortunatly the bundled it with software that sucks. Fobbit is great software that actually works. It runs on Windows, Linux and BSD.

Too bad you cannot buy VOIP blasters anymore. But you can still get them on EBAY for $50 a pop.

I use my VOIP blaster + Fobbit all the time as one runs 24/7 on my linux box at home and plugs into my phone system.