International audiences are seeing the usual fare of post credit clips in Amazing Spiderman 2. But, the only difference is, the clip doesn't have Spiderman in it. It instead, features [X-Men: Days Of Future Past](movie:203942) star Jennifer Lawrence as Mystique attacking William Styker's forces. This, apparently, is a joint venture for advertising purposes only. Sony and Fox have a mutual agreement to promote the new X-men movie.
As of right now, there is no news of any crossovers between Spiderman, the X-men, the Fantastic Four or Wolverine. But who knows. If they can get alone in this way, maybe crossovers are possible.
Also this has happened in France and will happen in England and we have no idea if this will continue with the US release.