The USPS Street Address Standardization Library allows you to standardize street addresses according to USPS guidelines from USPS Publication 28: http://pe.usps.gov/cpim/ftp/pubs/pub28/pub28.pdf.  This is useful for bulk mail compliance, and to match street addresses from different systems.  It standardizes street numbers, pre-directionals, post-directionals, directionals within street names, rural routes, street abbreviations, and unit abbreviations.

Unlike other address standardization software, there is no monthly subscription, and there is no maximum limit to the number of addresses that can be standardized.  It performs the standardization completely offline.  It is a perpetual license.