When I was studying for my Chartered Institute of Marketing qualifications a website that I used constantly was Mindtools. The website gives templates and easy to follow explanations on tools like the BCG, ANSOFF and Porters Five Forces.
I recently found out they had a completely free Mindtools App which I downloaded from the App Store. I’m not sure if they have released it on Android but I guess they would have.
Anyway I just thought I’d give it a plug as you might find it useful. If you’d like it you can download it from here.