Amid all of the other regulatory chaos out there, this one might have been easy to miss. That doesn't make it less important, though — or change the fact that you'll have to comply in less than a month.

Beginning on Jan. 1, 2011, paid tax return preparers who expect to file 100 or more income tax returns for individuals, trusts and estates (as well as preparers who work for CPA firms that, in the aggregate, expect to file 100 or more such returns) will be required to file those returns electronically.

The 100-return threshold will drop to 11 in 2012.

“To comply with the new law,” the IRS explains, “a tax return preparer who is subject to the electronic filing requirement and does not already provide e-file for clients must become an authorized IRS e-file provider, which means he, she, or the firm, if the preparer is a member of a firm, must obtain an electronic filing identification number (EFIN). It takes up to 45 days to obtain an EFIN so return preparers who have not started the process should start immediately.”

Additional guidance and resources are available in these frequently asked questions and in this IRS video: