If you're having a hard time getting iTunes and App Store links to launch from Google Chrome right to the app from your browser, MacStories editor-in-chief Federico Viticci has found a nice workaround in the App Store support community.
The workaround requires editing program files, so be careful if you're new. The issue deals with Chrome's protocol handlers. If your issue is with iTunes rather than the Mac App Store look for the line that says "itms" instead of "macappstore." Here's the hack from support community member Dahveed.
1. Close Chrome
2. Open "/User