Before the bell:

U.S. stocks were poised to open higher Monday, as investors felt encouraged by progress in Japan's nuclear crisis and AT&T's $39 billion deal to acquire T-Mobile USA.

Over the weekend, Japanese engineers made progress in cooling nuclear reactors that had overheated following the devastating earthquake and tsunami that struck the country on March 11.
Meanwhile, turmoil in North Africa heated up over the weekend. The United States and its allies launched an airstrike on Libyan military targets, in an effort to subdue forces of Libyan leader Moammar Gadhafi.
Investors also welcomed an announcement from AT&T (T) on Sunday, that it will acquire T-Mobile USA from telecommunications company Deutsche Telekom for an estimated $39 billion in cash and stock.
The new entity -- if approved by regulators -- would be the biggest in the United States, combining AT&T's 95 million customers with T-Mobile's 34 million users for a total of 130 million subscribers.
AT&T shares were up 3% in pre-market trading. Meanwhile, shares of rival Sprint Nextel (S) fell 12% in premarket. And Verizon's (VZ) stock edged up about 2%.
Economy: The housing sector will be in focus Monday when the National Association of Homebuilders reports on February existing home sales.
Economists expect sales to come in at an annual rate of 5.05 million in the month, down from 5.36 million the month before, according to consensus estimates.
Companies: Tiffany and Co. (TIF) shares rose 5.6% in pre-market trading, after the luxury retailer beat analysts' forecasts with earnings of $1.41 per share in its latest quarter.
Citigroup (C) shares rose 3.3% after the bank announced a 1-for-10 reverse stock split and said it plans to reinstate its quarterly dividend.
World markets:

Gold futures for April delivery rose $17, or 1.2%, to $1,433.10 an ounce.
The price on the benchmark 10-year U.S. Treasury fell, pushing the yield up to 3.33% from 3.26% late Friday.