How do I sharpen photos on my phone? I am looking for a photo editor app or website that will let me sharpen photos, preferably using unsharp mask. 

I tried several free photo editors from the market, but none of them lets me sharpen photos. I don't mind paying for an app, I just don't want to unless I know it is a good choice.
I have been using PicSay's free version and been happy with it.  I'll probably upgrade to the full version which has the ability to sharpen, but just haven't really had the need yet so I've been putting it off.  I'll report back if I do chip down.  

Another alternative would be to use Pixlr's web based editor: http://pixlr.com/editor  

Provided you have flash installed you can use their browser based editor that does have an "Unsharp Mask" filter.