Checkout the beginning of the auto app mart api
Here it will explain 2 ways of making api calls, via JSONP and SCRIPT. You can't use normal AJAX because its a security error to POST cross domain.
Currently we have 1 method, getNumberOfApps and it's used on the forum here to display the number of apps each developer has.
Feel free to use this api, and integrate it however you want. And as always let me know if you guys wanna see more from this.
Ill be adding methods, and access to the private API which you will require signed requests.