For existing apps with rolling map capability, look for AirspaceAvoid and Naviator. The latter is still missing CAA charts though, and I have requested twice that the developer should introduce them but there seems to be no interest in it. I believe more voices should sound towards the developer of Naviator as it's a fantastic app but next to useless without our local charts!
Pixie,
I too have a Sony Tablet S, very good bit of kit I am yet to try it in the air though. I would love to see a decent backup navigator, but the two I have previously mentioned don't do the job well (although AirspaceAvoid has UK charts, the UI is clunky and blocky IMO).
ft,
I believe the reason Aviation Tools requests the ability to make calls is down to the fact that the airport contact numbers are included in their database, so you can actually call them from the airport page. I cannot recommend this app more, it will list airports around you and all the information you could need.
James