Implement a tell a friend module when customer sighn in into the module(like facebook) using jquery

Question

Hi all

I have to create a functionality in which i want to implement a tell a friend module. Yes i know tell a friend module is not so difficult in other langauge like php asp etc. But the problem is i am working on jquery and i want to create a friends list when user is sighn in. Is gmail or yahoo provide any code to get the content using a user's mail id. Please note that i need this module in jquery