I\'m looking to geocode over 5000 addresses at once in a PHP script (this will only ever be run once).
I have been looking into google as a potential resource for doing
What you're trying to do is indeed not according to Google's terms of service.
That said, Google will start returning 'over-quota' responses if you don't pause at least 250mS between geocoding requests.
In practice, if you only make 2 requests a second you won't get throttled until the 2'500 day's limit.