AP just reported it - California Congresswoman Hilda Solis expected to be tapped as Obama's Secretary of Labor.
MSNBC listed Rep. Solis as the possible pick a couple hours ago.
This pick appears to reinforce Obama's emphasis on green jobs. Rep. Solis introduced the Green Jobs Act (HR 2847) in 2007. It was ultimately incorporated into the larger Energy Independence and Security Act (HR 6) that year.
A few other links on Rep. Solis:
Bio from her House website
Video of Rep. Solis speaking on the Green Jobs Act