Is it possible to dynamically Scale up instances?

Hi,

If load increases then to maintain the performance of application - 

Is it possible to scale up the instances dynamically on windows azure?

If yes, then How can I achieve it? Is it configurable or we have to apply some programming efforts in application?

Does it affect on pricing, as instances increases due to load?

And how to reproduce such scenario (like increase the load and verify thescaled up instances)?

Thanks

Navin