There are bunches of ways to get this done. I would take my time and choose carefully. It really depends on how much work you want to do. UPS offers shipment notifications that will automatically send an email with tracking to your customers. They are delivered in a standard format and they do everything. This service is requested at the time you ship the product with your shipping software. There are also a number of other shipping software products that offer a more personalized versions of this same process. This includes the ability to control the content of the email that is sent to your customers.
If you use or plan to use multiple carriers such as the US Post Office or FedEx, then things become much more complicated if you decide to do this yourself. There are also web services that do all this for you that you can link to your web site. Whatever choice you make you need to know that the URL links you put at your web site directly to the carriers are subject to change without notice and they do change. You should also make sure you understand and follow the carrier use policies with whatever you do. This is usually handled automatically when you use a web service or software package.
I hope this helps and good luck!
Bert
Tomaz,
First of all, I don`t think they understood your question correctly. Ok, so you are trying to create a script for your web site correct? Ok, First of all what type of Shopping Cart system are you using? From the Looks of it, if you are using php/mysql, you might be either using ZenCart or Oscommerce "Correct?" If you aren`t using any of the above mentioned carts, they posibility is that you my have to code the whole script yourself. UPS should have some sord of API that can be integrated seamlessley into your web application (Shopping Cart). An API is a simple script that if you have the know how, and the knowledge it shouldn`t take you more than 30 minutes to integrate it and your store is up and running. Now if you are using ZenCart or Oscommerce, Then things are less stressful simply log on to your control panel and where it says Categories, Click on Shipping and install the UPS module.
Then you must have a UPS account so you can enter your UPS account number and Password and you are ready. This can be done through your admin side.
Other than that, you might have to do it manually.
Best of Luck