Among the many gifts that the Internet bestows on non-profits, SmartyStreets surely has to be one of them.

Put in an address…..say,  1 Santa Claus Lane, North Pole AK…

and you will get back a listing of the correct postal address, including the zip+4 address,  a map of the location, the time zone of the location, and a slew of information about the address. If it is a commercial address, you may get the company name included.

If you are doing data entry, and want to confirm an address on the fly, you can do this interactively by just bringing up the web page.  SmartyStreets will return the address, corrected and formatted for a postal label. SmartyStreets will also perform minor corrections on an address.  For example, if you put in 10 Oak Street, and the address is really 10 Oak Drive, SmartyStreets, will suggest Oak Drive as a valid street name.
Great stuff!