Looking for a Mass Message Tool

Hi,

I'm looking for a tool that allows me to mass private message my competitors to entice their users to join our site.

My site is a social entertainment / network platform; we haven't launched yet, but want to get things in place.

Are there such tools out there or can someone create something?

Please let me know your thoughts.

Thanks

Mark

what is the platform of your competitor ? BTW this is considered spamming and would have a great effect on your brand value