Assorted tutorials:

• http://www.photoshopsupport.com/index.html
• http://www.graphic-design.com/index.html
• http://www.tutorialized.com/tutorials/Photoshop/1
• http://studio.adobe.com/us/search/sort?sort=topic&product=15&topic=0&type=all&level=all&x=8&y=6
• http://russellbrown.com/

I love the brushes from ObsidianDawn.  Here is a link to their site:

• http://www.obsidiandawn.com

A fantastic artist in the cartoon field... WOW!