Criando um app (aplicativo) para celular

Fábrica de Aplicativos
http://fabricadeaplicativos.com.br/

Appery.io
http://appery.io/

Appy Pie
http://www.appypie.com/

MIT App Inventor
http://appinventor.mit.edu/explore/

Tutoriais do MIT App Inventor
http://appinventor.mit.edu/explore/ai2/tutorials?

Android Studio (beta)
https://developer.android.com/sdk/installing/studio.html

App Maker
http://appmakr.com/