Following on the heels of their mobile video announcement, Cingular and AT&T last week announced that the Cingular Wireless brand would take the AT&T name. But what we believe was the more important announcement last week is of a new offer for unlimited free calling between wireless and wireline phone numbers.

Under a program called “Unity,” more than 100 million AT&T wireless and wireline phone customers will be eligible (under the plan’s terms and conditions) to call between any AT&T wireless and wireline phone without incurring additional wireline or wireless usage fees.

Wireless carriers have long had “mobile-to-mobile” plans that include free calls to some or all of the wireless carrier’s subscribers and others have added a limited number of wireline numbers that can be included in the free wireless rate. And unlimited wireline plans are also nothing new.

But we think the more important trend is that service providers like AT&T are now thinking of unlimited calling plans as a “one-network” approach across wireless and wireline networks. And that give companies such as AT&T and Verizon a distinct advantage when it comes to consolidated bundled pricing and features because they own both the wireline and wireless networks.

The AT&T Unity plans are, according to the company’s statement “available to new and existing AT&T qualified residential and small business customers in the company's 22-state service area, which now includes the local service area of the former BellSouth.”

According to AT&T COO Randall Stephenson, "AT&T Unity is just the beginning." We certainly hope so — we’re looking forward to the day when the only distinction between wireless and wireline services and features is the delivery media and we hope that bringing the two networks together will bring the best of each when it comes to customer features and services.

Steve Taylor is president of Distributed Networking Associates and publisher/editor-in-chief of Webtorials. Larry Hettick is a principal analyst at Current Analysis.