Until our old threads and documentation are restored, you can use the cached version of our site on Google. To access these pages, you should search for the keywords you want plus site:www.ubercart.org. This will pull up a set of listings, but you shouldn't click on the titles. Instead, click on the Cached links underneath each listing to see the version Google has saved. I'm not sure how long this will last, so we're implementing a plan to port that data back onto our site. That effort is being coordinated through this thread.

Example, to find PayPal related information, you'd search Google for the following:
site:www.ubercart.org paypal