visa to attend the conference

Dear Sir/Madam I have got an invitation from Organizing Committee of LCES 2012 to attend the conference" Low Carbon Earth Summit 2012 (Four Concurrent Events—New Energy Forum)" as a session speaker, at the Track 2-5: Strategies, Challenges and Opportunities of Small Wind Energy and Hybrid Systems of Forum 2: Wind Energy (WE).
So please could you tell me how could I get the visa from Baghdad-Iraq and what are the main document I have to bring with me.
I am waiting your replay soon