As of 8/9/9 Tracksw is still working for me. Some fans figured out how the 3.1 patch broke it so check out the changes you need to make here.
http://www.wowinterface.com/download...3-Tracksw.html
http://wow.curse.com/downloads/wow-a...ect-14831.aspx
http://www.wowace.com/projects/project-14831/
If you still want to change there is a good one called Wetspot, but it doesn't auto-switch based on Gather Info, just switches at regular intervals.