Looking for Call Centre Clients / Orders

I am planning to start a 100 seat call centre based in Bangalore, India. I would like to know what are the ways of marketing and how to get business for this venture. How do I get to know potential customers. Are there any agents / consultants in the USA or Europe, who can help me in procuring business on a long term basis ? Look forward to hearing from you. Best regards, Vinod (BTech, MBA)