SmartyStreets lets you standardize your addresses.
Verify - Make sure addresses are valid and complete before accepting them.
Geocode - All valid addresses come with latitude & longitude coordinates.
Standardize - Convert addresses into the proper USPS-preferred format.
Autocomplete - Suggest addresses while the user is typing (free with a subscription).
Process Lists - No software to install. Paste your lists into the website.
Now supports website keys