Ma Bell is back, and she could give Metro Detroiters a new alternative to cable television in 2006.

AT&T Inc., formerly SBC, is gearing up for a fierce battle with cable companies like Comcast Corp. AT&T is spending $4 billion to lay fiber-optic lines closer to half of the homes in its 13-state footprint, and it will use them for new services such as Internet-based TV.

The company hasn’t announced where the service, known as IPTV, will be introduced, but it’s expected to start its roll out early in the year.

Technology research firm IDC predicts about 1 million customers will sign up for IPTV this year.

Comcast, meanwhile, intends to expand availability of its digital voice service to more homes in southeast Michigan this year. It began offering phone service in this market several months ago.

Millions more people are expected to subscribe to an Internet-based phone service in 2006. The service, called voice-over-Internet protocol or VoIP, has been popular among technology enthusiasts and now is becoming more widely accepted.