SPRINGFIELD, Mo. --  Under a law that passed on Jan. 26, it is now illegal to unlock cellular telephones.

Oddly enough, it's at the hands of the U.S. Library of Congress.  It revised rules that apply to unlocking cell phones as well as "jail-breaking" popular models like the iPhone.  It's a rule the library looks at every three years.  It's called the the Digital Millennium Copyright Act.

If you bought a cell phone before Jan. 26, you can still unlock the phone.  If you bought one after that or if you buy one in the future, it's illegal.   That means you have to go through a carrier to get a new cell phone.

It comes down to copyright law.  While you do own the phone you buy, the government came to the conclusion that you don't own the software that comes with the phone. 

Jason Mohler, owner of Wireless Trendz, says the new law will affect prepaid companies.

He says, if you buy a used phone, you should still be okay.  However, the original purchase still has to be before Jan. 26, 2013.