Stocks Set to Open Slightly Higher  NEW YORK (Reuters) - Stocks were set for a slightly higher  open on Wednesday, boosted by wireless carriers Sprint Corp.  &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=FON.N target=/stocks/quickinfo/fullquote"&gt;FON.N&lt;/A&gt; and 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;, which agreed  to combine in a deal worth about \$35 billion.