As I had mentioned in previous email Esri has retired it's public-facing geocoding and routing services. These services are now only available behind their paywall (through an ArcGIS Online subscription). Esri gives UD a fixed number of credits on our subscription that we can use towards their various services. The cost for use of their Geocoder service is relatively expensive, as far as their services go. For example 300,000 would take nearly our whole allocation of service credits. However, for lesser numbers of geocode (for one-off needs) we can allow you to join our subscirption through an ArcGIS Online account. Contact us for more information.
For all other geocoding needs, I recommend the following desktop solution:
Download Disc 2: StreetMap North America (Detailed Road Network, Geocoding, Routing) from the UD GIS Data page.
You can then choose one of the .loc files in streetmap_na\data when it asks for an address locator in these instructions: http://resources.arcgis.com/