Aimster isn't just for America Online anymore. The Napster of instant messaging, rolling out a souped-up version Thursday, said it lets users of different instant messaging platforms communicate with each other, plus swap and share files. So far, said company spokesman Johnny Deep, the shareware will let users of AOL Instant Messenger and ICQ communicate. Both are AOL products. Aimster plans to add Yahoo! to the list "soon", and testing starts Friday for an Aimster that will encompass Microsoft, Deep said. "America Online now controls a lot of the market, but MSN and Yahoo! are creeping up," he said. "There are a fair number of people doing cross platforms." If successful, Deep said Aimster could link up more than 140 million instant messenger users. Aimster is a combined file-swapping and chat program that has signed nearly two million users since its launch on 9 August. It supposedly allows for the sharing of all kinds of files, not just MP3 music files. But unlike the granddaddy of them all, Napster, Aimster doesn't open a hard drive to anybody. Instead, users can create file-swapping "buddy" groups. Also unlike Napster, Aimster seems to have some cooperation from at least one record label. Capitol Records, a subsidiary of EMI Group, Aimster, and another file-swapper, Angry Coffee, are cross-promoting an upcoming release from the band Radiohead. If AOL and other IM companies are complaining about Aimster, they aren't doing so publicly. A spokesman for AOL said the company is "looking into" the latest Aimster release, but declined further comment. A source at the company, however, scoffed at the claims that the new release can actually link different platforms. The source said the Aimster technology "merely goes to the source, tracks down IP addresses, and lists them on their server". "That's not sharing," the source said. Deep said the relationship between AOL and Aimster has been "cordial", and he was unaware of any efforts by Web behemoth to block anyone from using Aimster. "If they have tried to block it, I haven't noticed," he said. He also doesn't expect much backlash from the other IM companies. To have your say online click on the TalkBack button and go to the ZDNet News forum. Let the editors know what you think in the Mailroom. And read what others have said.