Quick start – here are some pages that helped me get going quickly:
Defining your own attributes is easy. Getting them to display in a template is not. Cheat sheet:
http://www.sharpdotinc.com/mdost/2009/04/06/magento-getting-product-attributes-values-and-labels/
Don’t hack the Magento tree directly! You’ll be sad when you upgrade and your customizations are gone. Do this instead:
http://www.exploremagento.com/magento/override-a-magento-core-block-class.php
Grab all the simple child products for a configurable product (and then display one of their other custom attributes):
http://snippi.net/taxonomy/term/10
Updating stock through the SOAP API is unbelievably slow. The API doesn’t appear to accept more than one SKU per call! Use a script like this instead:
Some hints on how to get Magento to generate plain-text email:
http://www.magentocommerce.com/boards/viewthread/43928/
Kicking off an index process from the command line (using a custom script):