Wow, A lot of misinformation here! Here's what the BSA says about Federal Identification numbers on scouting.com:
http://www.scouting.org/filestore/mission/pdf/Fiscal_Policies_Procedures_BSA_Units.pdf
Yes, you certainly can file for a Federal tax identification number from the IRS. And you don't need to have employees, nor are you necessarily required to file any tax forms yearly to the IRS, depending on the Troop's (Pack's) chartering organization tax status. In other words, if the CO's status is a 501c3, you will not need to file a return (990 or 990EZ). Paying sales taxes is an issue you'll need to bring up with your own state taxing authority.
You can open up a bank account under your CO's Federal ID number if you wish, but sometimes the CO may not want to be bothered with you using their tax number, since they will need to come forward each and every time someone new needs to be added to a bank account, or another parent taken off for children who have aged out, or bridged.
But the most definitive statement I can make here is DO NOT USE A PARENT'S SOCIAL SECURITY NUMBER TO OPEN A BANK ACCOUNT FOR A TROOP OR PACK!
