We have recently developed a new tool, our Google Analytics Tag Validator, to help diagnose issues constructing URLs for advertising and tracking. If you’re tagging landing page URLs for AdWords, adCenter, Facebook advertising, and so on, this tool will help make sure that your composite URLs are properly constructed. Among other things, it alerts you if required tags are missing, and it shows you which values were read from the URLs. Note that it handles bulk URL submittal.
Please let us know if you have feedback/suggestions.