Angle Ruler Tool For Labels
From Omnidea:The Ruler Tool If the horizon line (or anything else for that matter) is crooked in a layer, click-drag the Ruler tool along the current (angled) horizon. Then, click the Straighten Layer button in the Options bar to automatically straighten the layer (based on the angle specified by dragging). If your using photoshop cs3-cs5 extended, with the ruler tool selected, uncheck Use Measuement Scale and then the ruler should measure in the units you have the rulers set to.
Omnidea Rulers allows to create on whole screen area a set of rulers, like most common graphic editors allows on their working areas only. Using the guide lines enables to measure and position objects with precision and it's incredibly useful in many fields, such as computer graphics, desktop publishing and web design. Rulers can also be used to select a screen area and take a screenshot that is automatically saved to desktop or copied to system clipboard.
What do you need to know about free software?
Pixel Ruler is a free application that claims to allow you to use your mouse to dynamically measure pixels. With it, you can accurately measure selected onscreen views in pixels, which can help when configuring image formats, creating graphics, and scaling images. It shows measurements in pixels up to 2,500 pixels in width or 1,500 pixels in height.
After a painless download and a surprisingly detailed installation process, a horizontal ruler appeared on our screen. There's also a ruler for vertical measurement. The interface consists only of these rulers; there are no navigation buttons or other controls. We would have consulted a Help file, but alas, none exists. However, this tool is extremely easy to use. Pixel Ruler floats above the desktop and can be dragged and dropped anywhere on the screen. As we moved our cursor up and down the ruler, a tiny box displayed the measurement from the end point in pixels. Clicking or double-clicking the ruler switches between the horizontal and vertical views. Right-clicking a ruler closes the program.
This application installs and uninstalls cleanly. Pixel Ruler doesn't require personal information or registration, nor does it ask for a username or password. As far as pixel measurement goes, surely there is a better option.