This software tutorial is actually a quick introduction to the fabulous USPS website. Now a lot of people love to hate on the post office - slow! expensive! incompetant! But really the USPS website is fantastic and has a lot of goodies in store for anyone who runs a small business. We used the USPS site exclusively when we first started - to look up package rates, order stamps and supplies, even print postage.
While this tutorial is USA-centric, your government's post office probably has a pretty good system themselves so check it out to see what free things they offer.
First thing you'll want to check out is the ability to print shipping labels with postage! This is great for when you dont want to haul yourself to the post office and wait in line.
Only problem is it's really tedious and slow and doesn't link into any sort of database service.