is there a way to query the play store for the version of an app without the need for user-credentials. I am aware of this unofficial API:
http://code.google.com/p/a
Found a suitable API via G+: this is the API: https://androidquery.appspot.com
example call: https://androidquery.appspot.com/api/market?app=org.ligi.fast
and this wrapper/code: https://github.com/androidquery/androidquery