Ed,
OK, Port forwarding your router is how you allow access to your web site from the general internet, if that is what you wanted then thats fine, all you then need to do is put WAMP Online.
wampmanager -> Put Online
This will not allow access to phpMyAdmin as the security on that is handled seperately, for obvious reasons.
If you want to be able to use phpMyAdmin from another PC
Forum:
WampServer English