Take a photo.
Copy it to your computer.
Look at the Exif data using your favourite tool.
I use Gwenview to view the Exif data and on my D5100 photos I see three "values" named "Shutter count", "Shutter Count 1" and "Shutter Count 2". I don't know why there are three different counts, but only the first have a sensible value. Shutter Count 1 always shows 0. Shutter Count 2 shows a different, random value on every photo. I've long been wondering about that, actualy.
The latest version of Picasa shows shutter count. Although I do my editing with the big names, I use picasa to go through my shoots (gotta love a free program that doesn't require confirmation upon delete.)
...hopefully screen shot attached.. in Picasa 3.. go to "info" (the blue icon directly over your time/date on the lower right of your monitor) then scroll ALL the way down - shutter count is 2nd to last.
If you are a Mac User, Preview will allow you to see all of the Exif data by choosing Show Inspector under the Tools menu then clicking on the Exif tab. The image number is the sixth item from the bottom.