Answer:
More than 1 link for this:
About getting notified you have a pm
http://dogaddicts.com/smf/index.php?topic=350.0How to:
Checking Messages
At the top of the page you will see the user info box

It will say Hey, [your user name] you have x messages, x are new. If you click on that, it will take you to the personal messaging page.
To send a message to a particular user:
On the left side of the page (when you are reading a topic) you will see this

If you click on the little computer screen it will take you to the personal messaging page, with a new message opened up and addressed to that user. Just type your messge and send. It doesn't matter if that user is online or offline, they will get the message.
PLEASE NOTE:If you enable email notifications for your pm's (personal messages) you will get an email with the content of the pm. IF YOU SELECT REPLY FROM YOUR EMAIL PROGRAM, THAT EMAIL WILL GO TO THE ADMINISTRATOR OF THE SITE, NOT TO THE USER WHO SENT YOU THE PM.
Either go back to the board and reply from your personal message page, or FROM WITHIN THE EMAIL ITSELF THERE IS A LINK THAT SAYS something like this:
Reply to this Personal Message here:
http :// dogaddicts.com/smf/index.php?action=pm;sa=send;f=inbox;pmsg=1014;quote;u=6
This is the link you would click on to respond to the message from within your email.

Here is why:
All mail from the forum, including notifications of post and pm's, come from the board adminstrator account.
That is minniesmom@dogaddicts
Hopefully this is clear.
If you have any questions post here
http://dogaddicts.com/smf/index.php?board=43.0