Here's a simple method to accurately straighten images using the Measure Tool. The below image was taken with a slight angle and will require some adjustment. We could simple Ctrl+T and manually transform the image into place, but often without accuracy, and is pure hit and miss...

Editor's Pick in Photo Editing, November 2005
This tutorial will introduce you to some basic photo manipulation techniques, which will let you create your own grunge photo in several easy steps.

Start by creating a new RGB image. I used the dimensions of 288 x 288 in the example. Make sure the background color is black and foreground is white. Next click on Filter > Render > Clouds, to create the base texture...

Start creating a new RGB image. I used the dimensions of 288x288 in the example. Create a new layer and fill it with gradient. You can use any color for it...

Start by creating a new image in the grey scale mode. I used the dimensions of 288 x 288 in the example. Click on the channels palette create a new channel. By using the Text Tool, type in the text (keep your text color white)...

Start creating a new RGB image. I used the dimensions of 288x288 in the example. Then create some text by using the Type Tool. Try using bigger fonts for it to look different and to stand out...

Start creating a new RGB image. I used the dimensions of 288x288 in the example. Choose the TEXT tool to enter your text. It could be of any color, background and foreground. Right click on the layer and Rasterize...

Start by creating a new RGB image. I used the dimensions of 288 x 288 in the example. Create a new layer. Now click the Channels tab, which is located between both the Layers & Paths tabs...

Before you start making this tutorial, go in the View menu and check if the Show Rulers and Snap options are on. Now drag the vertical ruler (left) to the center of your image. Do the same thing but with the horizontal ruler (top). Now there should be a cross right in the middle of your image...