These things are AMAZING!! I first found them through the photojojo site and have been on my want list for a while.
Low and behold when I talk to the brilliant Lisa, she tells me they are available at NOOD. So off I went to pick some up - $5 each. They easily attach to your phone or camera but I am keeping mine in a little bag altogether.
Once you pull off the cap, there is a sticky jelly ring that attaches to your phone or small camera. It easily attaches and detaches from each camera easily - the cap keeps it clean so it's ready to go when you want them.
There are lots of different ones available through photojojo but NOOD only had 3 - starburst, wide angle and 6 view. I haven't had much chance to play with them but here are a few examples:
Wide Angled Filter:
6 View Filter: