Top five free online resources that I find to be both educational and amazing are:
Mashable - Excellent resource to following marketing trends and much much more as well as providing information on additional free resources.
Flock - Social media tool designed to integrate most of your platforms. Makes it a little easier to navigate different sites.
Web Pro News - Excellent news resource
Giveaway of the Day - Always giving away free tools/software. Everyday! Has been great when it came to creating my logo.
Youtube - If you don't know how to do something, someone has already done it!