What does it take to implement a chat system in Python (Not asking for code just advice before I start my little project)

[Aseem Bansal]

I wanted to do a little project for learning Python. I thought a chat system will be good as it isn't something that I have ever done. 

I wanted to know what will I need? I think that would require me these
1 learn network/socket programming
2 find a free server to host my chat server
3 GUI development for clients

-I wanted to know whether these are all that I would need or are there more things? 
-Will I need to learn a web framework like Django? 
-Will I need to learn something for database management like sql for handling people's account names and password? 

Is google appengine good for hosting the website or should I look up at django hosting websites?

Any other advice for me(a novice programmer)?