According to the Boston Globe via Govexec:

 Rep. Stephen Lynch, D-Mass., the chairman of the House Subcommittee on Federal Workforce, Postal Service, and the District of Columbia and an outspoken advocate for federal labor unions, is apparently ready to throw his hat into the ring to succeed the late Sen. Ted Kennedy. According to the Boston Globe, the legislator from South Boston has taken out the paperwork to run in the January special election.