You can also use www.iship.com to track your packages by inserting

http://iship.com/trackit/track.asp?ACCOUNTNO=AISHIP&Track=<#TrackingNumber>&T=1

into your email template.
This way it will track usps, ups, fedex, and more just by the diferent tracking number.
This works better for me since I ship using both ups and usps.

Also is there a way to hide what the link says when it send the email since you cant use html code in the emails.