Do you do any kind of graphics work?  Do you sometimes need to know the dimensions of something you're looking at onscreen? Would you like an easy way to go from pixels to points to get these dimensions in pixels, points, inches, centimeters or millimeters? And would you like to be able get such a tool for free? 

Windows Ruler lets you do this.

It lets you easily move the ruler right next to the thing you want to measure and then adjust the ruler to get the dimensions.

I vouch for this tool, and believe you will find it very useful.

You can find it at Hexagora.com.