If you assign mobile phones to employees, they might be liable for a quarter of the applicable taxes if new IRS rules under consideration go into effect.

The idea is to take some of the burden off business owners' backs. Already, a notice issued this week allows employers to forgo "minute-by-minute" documentation of employees' company phone use.

"Minute by minute documentation really doesn't make any sense -- we've been hearing all about it, and we said yes it makes no sense," a senior IRS official told Telecommunications Online.

The employee tax-liability rule would assign 25 percent of an employee's phone bill as a "taxable benefit." Of course, if employees are required by your business to stay in touch via company Blackberrys and the like, having to pay the tax wouldn't seem like such a benefit at all.