Yesterday a blogpost announced a new feature for editing Wikipedia from mobile. http://blog.wikimedia.org/2013/07/25/edit-wikipedia-on-the-go/
Via twitter they confirmed that also Wikisource and all other project can be edited: do you confirm that? how is the user experience? Maybe we could file some bugs (if any), to improve the Wikisource editing... I don't have a smartphone, so I don't know if it is useful for us or not (what about the proofread extension?)
We can contact them at @WikimediaMobile on Twitter.
Aubrey