CDYNE's Reseller Web Service
The Reseller Web Service allow you to add a license key via a web service, Enable and Disable Keys, and more.
Sign up for a License Key
Sign up here - Create an account and click add key next to Phone Notify. Use that key in your development/gadgets. All for under 10 cents a Notify! Inquire for volume discounts.
This service is Free of Charge.