Thanks for your suggestion... but now I am actually considering another way. To give you an idea:
So whenever you click on someone's picture for example, it takes you to: http://localhost/MySite/profile.php?id=110
So there is a check to see if that member is your friend or not. And if I click on a member who is not (yet) my friend, I want to send him to msgToUser.php (which has it's own html) and echo something like "You and $thismember are not yet friends, Click Here to Send A Friend Request"... And then there is the "exit()" So I can exit the page, before that member's profile is run... Because if they are not yet friends, I don't want to be able to view the other guy's profile.
Now that I think about it, I may be better off just disregarding msgToUser.php and just having a jquery pop-up display the message....
Or.... is there a way to just make $msgToUser.php come up as sort of like a smaller sized pop-up window, on top of the current window (without proceeding to profile.php)? That way I could just stay on the same page, and just have the pop-up come up. I just want a simple way to be able to send a message to the user, with the option to have him take further action.