Question

Skype is a great product as Ron sugguested. There's also services out there that specialize in providing hosted phone solutions like ringcentral.com. I actually use Google Voice to forward calls to my mobile and home lines. You would just have to get an invite from Google. http://google.com/voice

Initially my company was based in a home office and I utilized internet VoIP telecommunications via Skype. There are several services that also provide you the ability to send and receive faxes through the internet. I think I was spending around $15/mo. for unlimited calls through Skype and an "efax" service. After moving into some corporate offices and filling out our infrastructure, I still utilize Skype and would recommend it as a very cost effective system that affords small businesses with a variety of other tools. Don't waste $5k-$10k on a traditional "box" and phone network, if you are cost conscious and do not have a call center level of call volume, just go with something similar to Skype. Save your money and use it for other business development purposes.