Nextel Profit Rises on Customer Growth  NEW YORK (Reuters) - Nextel Communications Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=NXTL.O target=/stocks/quickinfo/fullquote"&gt;NXTL.O&lt;/A&gt;,  the sixth largest U.S. mobile provider, on Friday said its  quarterly profit rose on strong subscriber growth, including  better-than-expected sales to young customers.