There are plans to enable the write API on the 'real' WMF wikis as well. Currently, it's only enabled on test.wikipedia.org (but you probably got that from the subject). If you want to test an application that uses the write API (i.e. action={edit,move,rollback,delete,undelete,protect,block,unblock} ), you can do so on the test Wikipedia. It could also be an idea to organize edit parties to test how the API and your application handle edit conflicts.
Before the write API is enabled WMF-wide, though, we need you to report your experiences with it. If you find a bug or have a suggestion for an improvement, please file it at Bugzilla [1] (don't forget to set Component to API). If it's working just fine for you, we *also* want to know: in that case please reply to or vote for bug 14210 [2]. This doesn't just apply to action=edit (which is probably the most popular feature), but also to the other modules.
Roan Kattouw (Catrope)
[1] https://bugzilla.wikimedia.org/ [2] https://bugzilla.wikimedia.org/show_bug.cgi?id=14210