Hey guys - I don't know why Google has to make everything so dang hard! I'll try to explain this for you in a simple manner...
The first step is enabling ECommerce on your Google Analytics account. This can be done by logging in, clicking edit next to the web site you want to enable it on, and under the main profile information box, click edit again and change the E-Commerce option to Yes.
This next part you may want to get your web designer to do (if you don't have one, try an outsourcing site like freelance, guru, or fiverr). You need to add a bunch of Google code to your shopping cart. Here's a link to the code http://code.google.com/apis/analytics/docs/tracking/gaTrackingEcommerce.html.
Other than that it's just tweaking stuff here and there until your happy with the reports.
-Duston
-------------------------
FINALLY... I gathered all my successful "traffic-getting" tactics from the past
few years (all free tactics!) and crammed them into a simple "Cheat-Sheet"!
You're welcome to grab a copy --> CLICK HERE