Can Anybody Identify This Mushroom?

Here are a couple of photos I took of a mushroom this past weekend growing under a bunch of young oak trees in central Wisconsin.  There were quite a few around so I thought I'd try to find out if they were edible.  They were in the debris of leaves/bark/sticks and were in the shade.  A very old oak tree once stood there and fell about 15 years ago and is rotting about 10 feet away.  Any ideas anyone?  You can right click and hit view image for a closer look.

Here's a closer picture...