02-18-2016 09:27 AM - edited 02-18-2016 09:28 AM
I think the best is probably www.shiprush.com although it doesn't actually run inside Act! it will update Act!.
02-23-2016 09:35 AM - edited 02-23-2016 09:36 AM
It also depends on what exactly you want you want to achieve with carrier integration?
If you just want a track a shipment, then www.aftership.com could work in a Web Info tab with a custom URL, where you're storing the tracking number in a field. i.e. https://track.aftership.com/1ZA9Y7170310894713
See this Knowledgebase article for more info on the Web Info tab: http://kb.act.com/app/answers/detail/a_id/25188