Fox Interactive Media (NYSE: NWS) has announced it will launch a free, ad-supported beta version of MySpace Mobile (previous carrier-portal efforts required subscriptions), dubbed MySpace Mobile Web (http://mobile.myspace.com). Fox will also launch ad-funded mobile web sites for FoxSports.com, game network IGN, AskMen and RottenTomatoes.com. The free service will run alongside the subscription services offered on various carriers (the subscription services could be cheaper, depending on how the data charges work out) and will let people send and receive MySpace messages and friend requests, comment on pictures and profiles, post bulletins, update blogs, find and search for friends, and view or change mood status. MySpace boasts 80 million users, and last month M:Metrics MySpace as the most used mobile social network in the US with 3.7 million users, compared with 2 million for Facebook. It’s still a fraction of the overall user base, and by opening up the service to anybody who’s interested Fox is obviously hoping the number of people using it will grow dramatically. The ads (handled by Millennial Media) will start with charter sponsorships in MySpace Mobile Web, while the other sites will have more traditional display-based ads.

Forbes reports that 70 percent of Helio customers subscribe to MySpace.

• MySpace Leads Mobile Social Network Use in U.S., U.K.; MSN’s Live Spaces Preferred On The Continent