Here's one that I use all the time.  It selects all "active" email
addresses that are associated with account-types with "PPP" in the
AccountType name (Business PPP, PPP Account, etc.).  I exclude one master
billing record that contains a little over 100 dial-up services (second to
the last line).  Of course you can go in and add whatever other criteria
you want:
SELECT DISTINCT sa.Email
FROM SubAccounts sa, MasterAccounts ma
WHERE sa.CustomerID = ma.CustomerID
AND ma.Active = 1
AND sa.Active = 1
AND sa.Email != ''
AND sa.AccountType LIKE '%PPP%'
AND ma.customerid != 837 /* Exclude IDT users */
ORDER BY sa.Email
I then take the output, copy/paste it into Notepad, do a search for " " and
replace them with "" to get rid of all spaces after each email address. 
I'm using Post.Office, so I've got an "everyone@talstar.com" account that I
have setup to forward to to whatever addresses I put in there.  I
copy/paste the email addresses from notepad into the forwarding area for
"everyone@talstar.com" and then send my mail to "everyone@talstar.com". 
Doing this prevents the recipients from seeing who the mail went to.  A few
minutes after I send the mail, I go back into the mailbox settings and
change the main address to something else, so that "everyone@talstar.com"
no longer really exists.  This prevents someone else from sending mail to
that address and spamming all of the selected users.
Josh Hillman
hillman@talstar.com