The following is taken directly from ign.com...
"Yeah, so that young Magneto movie that David Goyer was supposedly working on? It's dead. Not that this news comes as any great surprise to anyone who has even sorta been following the development of Fox's X-Men franchise lately.
Aside from the complete and utter lack of forward momentum on the project in recent months, word came last week that Bryan Singer was returning to the franchise he started to direct X-Men: First Class, an origin/prequel tale about Marvel's band of merry mutants. The thing is, part of that story is to involve the young Magneto and his relationship with the young Professor Xavier. That seemed to be the nail in the Magneto solo-film coffin, and now Singer has pretty much confirmed as much.
"This story would probably utilize some of the Magneto story because it deals with a young Magneto, so it might supersede that because this would explore that relationship between a young energetic professor and a disenfranchised victim of the Holocaust," the director tells The Hollywood Reporter. "But no, I don't see an exhaustion [of the franchise]. The X-Men universe is boundless. These are great characters. And as young characters, they are quite different than the characters we have seen in the contemporary movies."
Singer also says that in all likelihood his other project, Jack the Giant Killer, will go into production before First Class."