Django - HTTP Push Examples In Flex?

I am trying to create a simple board game (a kind of checkers), where users will be able to play online with each other using flex application as a client.

I am using django application to process the game on the server side. And I come across the problem, if one user made a move, I can send it to a server, but how do I let the opponent know about it?

The way I am thinking to do it is to create a timer and send requests to the server asking was opponents move done or not....But here we have 2 limitations:

1) Each client would produce big amount of requests (not sure how server will work if I have e.g 100 such clients)

2) If players will chose game with a time limit for example 5 minutes/per game it will be very important to show them situation on the board as soon as it changes (without a pause), but timer will send request only on timer event, so if for example I will chose tick interval to 5 seconds it will mean that 5 seconds another side will not be aware of the situation changes.