How can I see in the App store whether I am working secure
Assuming you were purchasing through Android Market (App Store is iPhone), credit card payments are handled by Google Checkout.  (More info: http://market.android.com/support/bin/answer.py?hl=en&amp;answer=105916 )

Google Checkout API is secure even though you won't see an HTTPS indicator like you would for SSL-enabled sites in a web browser (e.g. the green location bar in Internet Explorer).