Private message plugin:How to place private message button on profile

Hi

I'm trying to place a private message button on user profiles, so users can send a message directly to users when looking at their profile.

If possible, i would like the code for the button that i can place into the php file for the users profile. I would also like to place a button on post, that open up a private message to the post author.

Any help would be greatly appreciated.

Cheers