America Online plans to offer its 23.4 million US subscribers a premium anti-virus software service, McAfee VirusScan Online. The software will be available when subscribers download a new version of AOL's client software, AOL 9.0 Security Edition, in November.

AOl had previously charged about 2 milliion of its dial-up and high speed Internet subscribers an additional $2.95 a month to be able to scan incoming email, downloads and a user's desktop PC files.

"We don't think virus protection is something nice to have. It's a must-have," said Danny Kricher, executive vice president of AOL.