In App Subscriptions in Android
I am still looking for third party "in-App billing and subscriptions mechanism" but It would be worth taking your point of view on this.
I looked into "Google Checkout Beta Features" (http://code.google.com/apis/checkout/developer/Google_Checkout_Beta_Features.html) but it is in beta stage, Do we have other reliable alternatives for android market which could serve the monthly subscription.
You can now support in app subscriptions: If you have done in app purchasing of products before it's not much of a change, have to check for version 2 of the billing/vending though.
See the android developer blog:
You might want to take a look at PayPal's Mobile Payment Library. I'm not sure how well it supports subscriptions, though.