Visa to attend a summit

[sujji1985]

Sir/Madam

I am a engineer working in Hyderabad since 2 years. And recently i got a opportunity to attend a summit in USA (Washington) conducted by SAVE international.

They are ready to send all the required documents like invitation etc., and i am ready to bare all the expenses. As this is an rare opportunity , i don't want to miss it.

Could you please help me out in

-what is the best suitable visa i need to apply for.

-how long does it take for my visa processing (as the summit commends from 27th June)

-What are the required documents i need to be prepared with for my visa.

Please help me out with other details.

Any sort of help will be appreciated.

Thank you .