Please forgive my lack of knowledge on this subject, but I would very much like to know if it is possible to communicate with webservices on an Android device, running in an apk made with Unity. Where should I start learning about this?
The WWW class allows you to make HTTP requests to arbitrary URL’s. As far as I know, it works just fine on Android.
Docs:
http://unity3d.com/support/documentation/ScriptReference/WWW.html