In what could be the first step toward network convergence, AT&T and Cingular today announced they are linking AT&T Yahoo content on the SBC wireline network to the Cingular content deck, giving customers a unified content portal across the two networks.

Called AT&T Yahoo Go Mobile, the service will take much of the Yahoo content portal functions on the carrier's DSL service and graft them into the cell phone, for now the Nokia 6682, a Symbian OS/Series 60-powered smartphone on the upper-high end of the pricing scale. The service will allow customers to access their e-mail; photos; address book; calendar; Yahoo Messenger; and Yahoo imaging, Web and search tools, as well as receive the customized news, weather and sports they receive on the wireline portal.

The service, however, goes further than replicating those functions on a wireless application protocol (WAP) browser window. It uses an on-board application that accesses the same databases as the DSL service, allowing customers to seamlessly synchronize their data between the PC and the phone. A contact updated on the phone will be reflected on the broadband portal, AT&T officials said.

AT&T said that Go Mobile fits precisely into its strategy to more closely integrate its three highest-growth assets: its fledgling TV service, DSL and the wireless network.

"We're blurring the lines between the PC and the wireless phone so that consumers can stay in touch, check e-mail, get updates, news and weather--minute to minute, day to day--regardless of where they are or what screen they are watching," said AT&T Consumer Chief Marketing Officer Scott Helbing in a statement

AT&T, along with Cingular, have both been deploying IP multimedia subsystem (IMS) architectures in their network, which would enable--among other things--cross-network convergence of services. By using session initiation protocol as a common language, the IMS control planes of the two networks can federate services across what were originally isolated systems. AT&T and Cingular, however, are using legacy systems to power Go Mobile, using IP as a common platform for the Internet content stored on the network, but stopping short of enabling a full end-to-end bridge between the PC and phone using SIP.

Those types of applications, however, are expected to emerge soon, though they are likely to occur within the two operators' networks, instead of between them. Cingular is promising a fully SIP-powered peer-to-peer communications application over its 3G network by mid-year, and AT&T is looking to more closely integrate its wireline service by moving its various voice-over-IP platforms onto IMS and creating merged services across the television and telephony networks--caller ID on the TV screen, for instance. Their plans to converge services between the 3G and next-generation wireline access networks over IMS won't take place until next year.

The Go Mobile service, however, may be the carriers' attempts to introduce convergence ahead of IMS, targeting select applications and customers for more 'lifestyle-oriented' applications. Those services won't come cheap though. AT&T won't charge additional fees to access the Yahoo portal from the wireless network, the service requires a data plan over Cingular's EDGE network (no handsets are yet available over Cingular's UMTS network), and the phone price is prohibitive. The Nokia 6682 is a hefty multimedia device that retails for about $400. Cingular, however, is offering it for $200 after rebates and a two-year contract. The Go Mobile application will only be marketed in the SBC 13-state footprint, where it will be pre-loaded on handsets sold at Cingular stores.