Here is an update for X-Men First Class, X-Men 4, and Wolverine 2.
All I know is that I am happy that Bryan Singer is back as the director. If and when he does X-Men 4, I really hope that Fox doesnt pull a Sony ala Spiderman 4 and recast the whole crew. Considering they brought singer back to direct the franchise, I am confident that majority of the core actors will return. Its almost guaranteed that Hugh Jackman will be back because they would never film an X-Men movie without him in it.
http://movies.ign.com/articles/107/1078846p3.html