ESPN service on the Xbox 360 may be just the start.

Microsoft is in talks with other networks about bringing additional subscription TV services to the Xbox and other devices, according to a Reuters report today based on anonymous sources.

Microsoft has tried for decades to increase its presence alongside the TV. That has led to all sorts of partnerships with networks and cable companies, including some that are now offering a modified version of the Xbox to subscribers as an alternative cable box.

Meanwhile consumer-electronics companies from Apple down are offering a range of new gadgets that connect TVs to the Internet and provide a platform for TV and movie companies to offer rentals and subscription services.

An excerpt from the Reuters story:

The maker of the Windows operating system has proposed a range of possibilities in these early talks including creating a "virtual cable operator" delivered over the Internet for which users pay a monthly fee.

Other options include using the Xbox to authenticate existing cable subscribers to watch shows with enhanced interactivity similar to how pay TV operators have sought to do over the Web, said these people.

Microsoft has already been building up the lineup of entertainment options on the Xbox, which is becoming more of an entertainment hub and an option for people trying to get Internet video content onto their TV.

I'll bet the latest round of talks are focused particularly on new digital TV boxes based on Windows Media Center that Microsoft and hardware companies will unveil at January's Consumer Electronics Show. These $200 to $250 boxes function as TV tuners and gateways to online video services such as Netflix.