A very nice and really working recovery tool is PhotoRec. It’s a very cool commandline tool for Linux which is able to recover all images on a SD or MMC card that have been deleted accidentally. In my case my fingers where faster than my brain and so I had kicked three rally awesome images :-/. But happily I had PhotoRec that recovered them in some minutes.
You’ll get more information here. It can be downloaded in a bundle with TestDisk only, which is also very useful.
For safety’s sake I have uploaded a copy of the latest release here (x86_64).