OS X has a nice screenshot feature. It’s fast and easy to use: just press Cmd-Shift-4 and select your shot, which will appear in the desktop. By pressing space, you can switch to window shot.

The problems come when you want to share your screenshot on, say, IRC. Direct transfer (DCC) is usually too much hassle for that, and some clients do not support it. What you usually do is upload the picture to the web, and link it.

You could just manually upload the file the screenshot feature produces. But I’m spoiled by the use of Nyazo on Linux, and I wanted better.

So in a few minutes you can tweak Nyazo’s Linux script and end up with this:

#!/bin/sh
screencapture $1 /tmp/nyazo.png link=curl -s http://nyazo.ru/upload.php -F "id=''" -F "imagedata=@/tmp/nyazo.png" rm /tmp/nyazo.png open$link

Save it as something like /usr/local/bin/nyazo and make it executable (chmod +x <file>). Then open Automator and create a new Service. Add the “Run Shell Script” action to it, write /usr/local/bin/nyazo -i to it, and save it.
Now open “Keyboard” in “System Preferences”. Go to the “Shortcuts” tab, and select “Services” on the left. At the end of everything, you can bind the interactive Nyazo Service you just created. I have it bound to Option-Cmd-Shift-4.