iPhone / iTouch programs for photography

Any of y'all have suggestions for photography related programs on an iPhone?  Or droid for that matter?

I realized that I always carry around this little computer in my pocket and figured there's bound to be some cool stuff I'm missing.  Searching in the app store gets a lot of results, but most of it is paid and I don't feel like having something wind up being trash and out the money for it.  I'd feel better trying something following a recommendation or two.

I have played around with "Toy Camera" on the iPhone.  It can give you some interesting looks directly out of the camera.

There's several depth of field calculators out there. I use Strawberry and DOFcalc on my android phone.