Starting this month, telephone customers in the United States <A HREF="http://news.com.com/2100-1037-5105248.html">must be allowed to transfer their landline number to a cell phone</A> when signing up for new services, the Federal Communications Commission has ruled. News.com reports that an order issued Monday and supported by all five FCC commissioners requires landline phone companies to make way for what's called "porting" of phone numbers in the nation's largest 100 markets beginning November 24. Similar rules affecting customers who switch between cell phone providers also are set to take effect at that time.