Most of Madonna's New York fans couldn't squeeze into her one-night-only mini-concert Sunday at Roseland, and then came more bad news.

Most of Madonna's New York fans couldn't squeeze into her one-night-only mini-concert Sunday at Roseland, and then came more bad news: Her only other appearance would be in London later this month. But now everybody — or at least, everybody with a computer — has an invitation to the British gig. And it may turn out to be Madonna's biggest crowd ever. The Microsoft Network announced yesterday that her show at London's Brixton Academy on Nov. 28 will be broadcast live on the Internet. The company said the cyber-concert, to be witnessed by 3,500 flesh-and-blood guests, could challenge the world record for an Internet audience — currently held by Paul McCartney's Web-cast from The Cavern Club in Liverpool last year. That event drew 3 million surfers. The concert, on www.msn.co.uk/madonna, will be Madonna's first online concert, and underlines stars' growing awareness of the reach of the Web.