From the April 2007 issue of Entrepreneur

Just when you thought they couldn't possibly invent anything to make communicating easier or cheaper, they did--"they" being a San Mateo, California, startup called TalkPlus.

You know those great virtual PBXs from companies like Covad? How would you like to have those extended calling features on your cell phone? No, you won't need a $500 smartphone, and you won't incur those ridiculous web tolls levied by providers like Sprint. TalkPlus will work on just about any latter-day cell phone and over the most widely available voice networks.

You can assign up to 10 fully functional phone numbers and voice-mail boxes to a single cell phone--each good for incoming and outgoing calls in the area codes of your choice. Included are common phone extras like caller ID and the kind of call tracking only lately realized in the virtual PBXs of VoIP providers. TalkPlus turns your cell phone into a cellular PBX.

For $8.99 to $36.99 a month, TalkPlus Basic plans include between 60 and 1,000 minutes of talk time on a second phone number with its own voice-mail box distinct from your regular cell service. Use it as the main number for your multinational, your private line or as a customer sales line. When a call comes in, you have plenty of options: You can answer it, let it roll to voice mail or a busy signal, forward it to another "extension" or send it to a landline to reduce cell charges.

If you want more than two numbers, subscribe to TalkPlus Pro for $16.99 to $44.99 a month. (Each additional line--up to 10--is $2.99 a month.) The numbers can be in different area codes so you could, say, provide toll-free sales or support to out-of-state customers. You can also have 10-way conference calls or clone your home and office landlines so calls to those numbers find your cell.

You set your preferences on a private web page where you can determine call screening rules, white-list or blacklist incoming numbers, analyze and download the calling history of each new "extension," and synchronize your web and cell phone books. TalkPlus lets you play voice messages in any order you like on your phone or web page.

With technology like this, your cell phone may wind up being the only phone you ever need.