ABC will offer some of its most popular televesion shows free on the Internet in a two-month trial. Commander in Chief and Alias along with Lost and Desperate Housewives will be available on the Web in May and June, starting the day after they are first broadcast.

Leading U.S. media companies are experimenting with ways to deliver programs via new technologies and still maintain revenue as viewership for their prime-time schedules slowly erodes.

Viewers will be able to pause and move between "chapters" in an episode but will not be able to skip ads that are technically embedded.

Advertising revenue will support the trial run on, with advertisers AT&T Inc., Ford Motor Co., Procter & Gamble Co. and Universal Pictures already signed up.

iPod users can currently download selected ABC television episodes 24 hours after they are shown for a small charge using Apple's iTunes service.