Chris DeWolfe, the founder and chief executive of MySpace, will step down, though a date has not been set for his departure, the company said Wednesday.

DeWolfe, who has helmed the Beverly Hills-based social networking site since before its acquisition by News Corp., will remain on the board of MySpace China and serve as a MySpace advisor but will not renew his contract, the company said in a press release.

Former Facebook Chief Operating Officer Owen Van Natta is reportedly the favorite to replace DeWolfe

MySpace did not specify why DeWolfe is stepping down except to say that it was by mutual agreement with News Corp.’s Chief Digital Officer Jonathan Miller.

Miller also is in talks with Tom Anderson, MySpace’s president and another of the company’s founders, to assume a new unspecified role at the company.

On Wednesday afternoon, a MySpace spokeswoman said DeWolfe’s resignation would be effective immediately. But in the evening she said a date had not been set.

MySpace is the largest social networking site in the United States but its growth has recently lagged behind Menlo Park-based Facebook. Some analysts have speculated that Facebook will overtake MySpace in terms of total users some time in 2010.