I'm looking into using this module on a project, and am a developer who could not only test, but help out (I've worked with other parts of the Paypal API before).

At the moment I'm just trying to get started. Your project page says to go to x.com and register by clicking on My Apps. But I can find no such link on x.com. There is a Sign Up for X Commerce link which just says to register at Paypal. I can get the API_Username, password, and signature from the Paypal sandbox account. But not the API_AppID.