It seems fairly common today for websites to perform some address verification behind the scenes. For example, the 4 digit extension on zip codes is commonly filled in. In addition to filling in the 4 digit zip code extension, I would like to know what county the address belongs to.
This will be utilized in an ASP.NET 3.5 application that already has all the hooks in place for ASP.NET AJAX along with jQuery.
What services out there would allow for this to be done? Web services, 3rd party includes, etc.
UI Structure
ADDRESS_LINE1 ADDRESS_LINE2 CITY STATE ZIP
If you’ve got cash, NetAddress is built for .NET.
It’s also been asked on SO before: here.