I work for Sky, albeit in a rather lowly part time manner (I'm a full time student) we have the means to make suggestions to the business etc and whilst I'd hope this is something Sky would have thought of previously I did make the suggestion to release official Android apps.
There is an unofficial sky+ app, but it's paid. I bought it and it works rather well. The only down side is that it doesn't store your username and password, so you always have to log in when making a recording. Also as it's paid, if an official app is ever released it'd be money down the drain. I think it's called Sky Remote Record or something similar.