Variety are running an update on exactly how the current Writer’s Guild strikes shall affect the big budget Hollywood productions, specifically Michael Bay’s Transformers 2 and the Wolverine X-men spin off:

DreamWorks/Par’s “Transformers 2″ is far enough along to proceed with pre-production, location scouting and advance VFX work, but will face serious issues if the strike continues for several months. Michael Bay’s megabudget sequel isn’t set to start filming until June.

[…]

Fox is moving full speed ahead with its “X-Men” spinoff “Wolverine,” even though many roles are still uncast. Unlike “X-Men,” “Wolverine” rests solidly on Hugh Jackman’s shoulders.

If you don’t understand the cause of these strikes, I recommend watching this video which explains everything you need to know: