"George Ou shows how with the help of open-source VOIP server Asterisk you can start your own telecommunications company for under $6000 '...you can build a phone system that can support 72 analog telephones or fax machines, 100 IP hard or soft phones on site or remote, a T1 line to the public telco for 23 simultaneous external PSTN connections, multiple IP-based IAX trunks to multiple remote offices for seamless toll-bypass 4-digit dialing, IVR, and almost unlimited voice mail for everyone – for under $6,000 in a 1U chassis. Such a price point is easily 10 or more times cheaper than a commercial alternative,' writes George." (Thanks /.)
The only thing George forgets is that getting the bandwidth installed to share the connections with other offices over the internet can be an expensive proposition in itself. Before you get too excited, you might want to check out DS1 prices in your local area for both voice T1s and intenet T1s.