Submit business proposal

I would like to submit a business proposal to an executive of a large web based technology and media company, how do I go about this.
I've been to the company site and it gives information about the executive but does not list contact details.
I've also been to portfolio.com but I am required to have the recipient's email address if I want to send an email.
Are there agents or web sites that specialise in this type of service ?
Am I approaching this by the wrong methods ?