Web services Programming Tips and Tricks: WSDL file imports

This tip explains the nuances of the two types of import statements found in a Web Services Description Language (WSDL) file. Import statements are easy, right? Just about every programming or interface language has them; and if you're reading this tip, you probably know everything there is to know about imports. So, why should you read a tip about Web Services Description Language (WSDL) file imports? For one thing, two types of import statements exist: XSD imports and WDSL imports. For another, their respective behaviors are not quite identical. Lastly, it's a good idea to know the relationship between the two.

http://www-106.ibm.com/developerworks/webservices/library/ws-tip-imports.html