The long shadow design trend was huge about a year ago. Like many other trends it quickly got abused and most people stopped using the design style, instead completely flat styles are used more commonly. When used correctly and not overdone the long shadow design style can still be an interesting way to draw some attention to certain design elements.
Here is a great collection of 14 long shadow resources, in no particular order. Photohoshop and Illustrator actions, icons sets and even generators so you can easily create your own longs shadow graphic. Have fun!