See the Ubercart 3.x User's Guide for a great set of tutorials for setting up and using Ubercart and Drupal. Topics covered are:
- Installing Drupal
- Common Drupal Terminology
- Adding functionality to your Drupal/Ubercart site
- Configuring your modules
- Configuring Ubercart
- Shipping, Paypal, and taxes
- Creating products and configuring the catalog
- Overriding the catalog and creating product attributes
- Creating product kits, store stock, and order status
- Launching your site, Ubercart reports, Drupal themes, and add-on modules
