Williams did not indicate in its filing how many shares it plans to float or within what price range they might be offered.
Williams Communications is the telecommunications business unit of Williams Companies, a conglomerate that also distributes natural gas.
Williams also plans a ten-year note offering.
SBC is expected to use Williams's planned 32,000-mile fiber optic network once it gains regulatory approval to offer consumer long distance voice service.
In February, Williams said it would speed its network construction plans and spend an additional $2 billion to complete the network a year early. The company expects to have 26,000 fiber optic route miles finished by the end of the year.
Williams is among a handful of companies building state-of-the-art fiber optic networks designed to carry packet-switched voice, video, data, and Internet traffic. Others include Qwest Communications International, Level 3 Communications, Frontier, IXC Communications, and Enron.
As demand for bandwidth and high-speed Net access increases, Wall Street is waking up to the potential market for communications network companies, including fiber optic backbone carriers such as Williams and "local loop" providers that connect those networks with customers' homes and offices.
The Williams IPO registration comes on the heels of the successful offering by Rhythms NetConnections, a data-focused competitive local phone company. The Rhythms IPO, especially strong for a so-called facilities-based company, helped propel competing digital subscriber line (DSL) provider Covad Communications to a new 52-week high today.
Covad shares gained more than 16 percent to close at 81.5. The stock has traded as high as 75.875 and as low as 31 since going public in January.