Hey Tim,
Here is what we have:
UPS
URL: http://wwwapps.ups.com/etracking/tracking.cgi?TypeOfInquiryNumber=T&InquiryNumber1=<EpicorTrackingNumber>
Placeholder: <EpicorTrackingNumber>
FedEx:
URL: http://fedex.com/Tracking?tracknumbers=<EpicorTrackingNumber>&cntry_code=us
Placeholder: <EpicorTrackingNumber>
USPS:
URL: https://tools.usps.com/go/TrackConfirmAction_input?strOrigTrackNum=<EpicorTrackingNumber>
Placeholder: <EpicorTrackingNumber>
If you use LTL Carriers, you should be able to reach out directly to the individual carrier for their Tracking URL, or occasionally I can locate them via a web search.