Legal sparring focused on digital-music delivery has driven music sites straight up the Internet charts, according to PC Data’s top 100 Web site ratings for April.

Microsoft’s recently re-launched music and radio download site saw the largest gain, shooting from number 358 in March to number 66, with 5.8 million unique users in April. also grew, climbing up the Web site hit charts from 28 to 22, with 11.7 million users. jumped from 102 to 96 (4,700,000 users), and Napster entered the top 100 for the first time at number 99 (4,666,000 users), a climb of 59 places. also gained traffic in April, rising from 64 to the number 50 slot.

Mike Piccione, PC Data’s Internet analyst, said: "Digital music is inciting both controversy and competition – and ultimately traffic to the Internet. In the end, it is this traffic that will determine how we ultimately listen to Bach, the Beatles or Britney."

Yahoo remains the most popular site on the Web, attracting 4,9455,000 users.