here is another list of useful apps for Wien&Umgebung. although these point at the itunes store, almost every app has its android counterpart as well.
AnachB - and you will forget qando forever. this app calculates with bike roads and city bikes as well
bikar - if you are using the wiener city bike system, this app is your new bible
Freewave - free hotspots in town
willhaben.at - mobile app for the well-known austrian ebay site, if you willhaben
Post - official app of the austrian post, office finder, follow your package, etc.
Apotheken - apothekes, so drug shops in town, also during weekends
Öffnungszeiten - cause austria is a land of strict opening hours
susi.at - layar app specialized for wien, shows all shops, restaurants, hotels, services, etc. around your current position
Gelbe Seiten - yellow pages for austria
Gelbe Seiten Notfall - whom to call in case of emergency situations?
Waze - gps drivers navi combined with social media, so the app shows and calculates ways using realtime data of other further users also on the road
Spritpreise - where to get the cheapest fuel?
Unterwegs - prompt motorway news directly from asfinag
ÖBB Tickets - railway assistant and online ticket office. note: do not buy any online tickets to budapest or bratislava! keep paper tickets for your eastern destinations
Westbahn - similar app for the private railway service company between Wien and Salzburg, towards Munich
Wandermap - touring and mountaneering assistant app with pathfinder
Touren - same touring and skiing guide for Zell am See / Kaprun region
Taxi 40100 - who uses taxi in Wien anyway?
Wien isst - cuisinie and restaurant guide
Vivino - direct your iphone at a wine bottle and it shows all product info available
Weinkaufen im Supermarkt - the name tells it all. spar gourmet or interspar shops offer a vast selection of wines
Niederoesterreich - regional tourist app
iAustria - tourist guide for austria
Radio Austria - radio stations over the land
pons.de - dictionary app, with local austrian vocabulary included