U.S. unemployment may be a concern, but tech companies are telling Congress they need more skilled workers from overseas. With the Apr. 1 application deadline for H-1B specialty worker visas looming, tech giants like Microsoft (MSFT), Oracle (ORCL), and Google (GOOG) are stepping up efforts to raise the cap on the number of visa workers they can have access to each year. Microsoft's Bill Gates argued in Congress (BusinessWeek.com, 3/12/08) for the second straight year that there's a severe shortfall in U.S. science and engineering talent, and predicted that for the fifth straight year the cap for worker visas would...