Thanks to narcussist, I found out how to make this happen. To save anyone else the aggravation of my search, I decided to post the technique for getting PHPBB to use Gmail's SMTP server for general email tasks (especially validating new users). If this is too basic, please excuse the post. I want to insure that even newbies could figure this out. BTW, I set up PHPBB using Windows 2003 Server and IIS 6. The technique will probably be a bit different if you're using Linux.
1. Go to the Gmail site. Register for an account. Make sure you can send and receive emails to and from this firstname.lastname@example.org
address using the Gmail web interface. This will confirm that your Gmail email box is functioning properly, and can send and receive email to and from the outside world.
2. Using the menu at the top right edge of the main Gmail window (the one that shows up after you log in), click on Settings, and then Forwarding and POP / IMAP. Under POP Download, click either Enable POP for all Mail, or Enable POP for Mail that Arrives Now (which ever suits your purpose). Configure anything else that appeals to you too. Exit from the Gmail Settings Window after saving your selections (this is important).
3. Using GMail's instructions at
Configure the email client of your choice (the one installed on your computer - Outlook, Outlook Express, Eudora, Thunderbird, etc) to access your Gmail account using POP and SMTP services. Confirm that you can both send and receive mail using your email client. This will prove that Gmail is responding to POP and SMTP commands from outside pieces of software.
4. Install PHPBB with the database of your choice, and make sure that everything (except the email-related pieces) is working. Go into the Administration Control Panel in PHPBB, and navigate down to the Email Settings. Select Use SMTP for Email. For the SMTP Server Address, key inssl://smtp.gmail.com
Do NOT use the TLS entry seen in some other posts on this site. Unless you install TLS support in PHP (which I could never figure out how to do), this will cause the email features in PHPBB to fail.
5. Key in an SMTP Server Port of 465
6. Key in the Authentication Method for SMTP as Login
7. Key in the SMTP Username that you created in Gmail, making sure that you use the entire Gmail address in the window
8. Key in the SMTP Password that you used when you set up the Gmail account.
9. Hit Submit.
10. Go into the Windows directory on the IIS / PHP / PHPBB server, and edit the PHP.INI file that you placed there. Uncomment (by removing the ; from in front) the following command in the file.
Reboot the system.
11. Test the New User Validation System in PHPBB by registering a new user. To see if this worked, check the Gmail email box to see if there's a message. The From Address will be the Gmail Address that you set up at the beginning of this process.
12. If you don't find an email message, check any Spam systems that you have. You might have to Whitelist the email address so that you see the messages. If the message is nowhere to be found, go into the Administration Control Panel, and using the Tabs at the top of the screen, select Maintenance. On the left side, select Error Log, and see if there are any SMTP errors showing up. This might give you an idea of what's going wrong.
Again, I'd like to thank narcussist who responded with help when no one else was able to.
Merry Christmas and Happy Holidays.