"A 27-year-old man described as one of the world's most prolific spammers was arrested Wednesday, and federal authorities said computer users across the Web could notice a decrease in the amount of junk e-mail. Robert Alan Soloway is accused of using networks of compromised "zombie" computers to send out millions upon millions of spam e-mails. "He's one of the top 10 spammers in the world," said Tim Cranton, a Microsoft Corp. lawyer who is senior director of the company's Worldwide Internet Safety Programs. "He's a huge problem for our customers. This is a very good day.""