I was flipping through blogs today and I noticed someone had a tag cloud for their labels. I looked and looked through the widgets and couldn't find one. Then I tried Google and found this. There were about twelve other results but the one I'm linking to seems like it might be the original.
I followed the instructions in the post carefully and I had a tag cloud on my page. I did have to set cloudMin = 0 in order to get all my tags to display but once I did that I had a perfect cloud.