After adopting the more innocuous name of a company it acquired last year, “FriendFinder Networks,” Penthouse Media Group filed for a $460 million IPO on Tuesday.

Penthouse bought FriendFinder– which runs sites that help subscribers find friends of all sorts, from FrenchFriendFinder.com for those interested in working on their French, to hook-up sites AdultFriendFinder and BigChurch.com, a site for single Christians –for $500 million a year ago.

The idea was to tap into the online adult market and become less of a publishing company than an internet company. The purchase also included popular video chat site cams.com, an adult site which helps new friends connect visually.

In March, Penthouse had said it planned to raise $250 million in an IPO in the second quarter. But as the IPO market floundered in the second half of 2008, those plans got scuttled.

FriendFinder joins a pipeline of IPOs facing a harsh climate. But this IPO in particular faces two major challenges, despite the old adage that sex sells: the proceeds will be used largely to pay off debt, something investors generally resist, and arch-rival Playboy has seen its shares wilt in 2008,  falling 78 percent.  What’s more FriendFinder Networks’ profits fell more than 20 percent between 2006 and 2007.