Doug's AppleScripts has a nice overview of Applescripting changes to iTunes 4. Frankly I'm a little dissapointed that they haven't made shared track information available via Applescript, nor anything related to the new store.
“Access to shared libraries via AppleScript is off limits, let me get that out of the way right up front. There is no way to access any information about tracks in a Shared Music playlist. Not no way not no how. Ditto iTunes Music Store.”
Apple's got some great momentum going with their new Music Store. They need to start an Associates Program immediately, then get Web Services up and running. I'd love to offer individual tracks for sale on my site (okay, my site would generate enough in associates sales to buy a small cup of coffee, but you get the idea.)