First up is the OBB Help Desk, which can help answer some basic "how should this be filed in OBB?" questions.
The OBB Help Desk: 1-855-TBB-HELP
There is also an IRS Help Desk. This one will put you on hold for longer because of the higher call volume they experience, but they can help with any and all aspects of tax law. They can also locate a clients AGI for the 2009 tax year if the client wishes to file their 2010 taxes electronically.
The IRS Help Desk: 1-800-829-1040