Inspired by the Cloth Texturing Tutorial. Meant for Photo Impression, but may be used with other tools.
Step 1:
Create an image with the shade of brown you would like your wood to be. May I suggest using a 512x256.
Step 2:
Using the brush tool (of any size) draw some vertical lines, horizontal lines, or some cirlces on the brown image. If preffered, you can just make random scribbles with the brush

The color for the brush should be black, and the Intensity should be set to 100.
Step 3:
Still using the brush tool at 100 Intensity, choose a lighter (or darker) shade of brown, and start painting around the black edges. It doesnt need to be neat, so dont worry about it
Step 4:
Apply a 100 Intensity Blur to the Image.
Step 5:
Apply a 100 Intensity Color Embossing.
Step 6 (optional):
If you want the wood to have a grainy look to it, add some filmgrain to it.
Step 7:
Last but not least, resize it to a square image, and viola, you now have a new wood texture.
Hope this can help some people with texturing. Though its not professional (like Arras's cloth tutorial) it should help some people. Hopefully the images will show, I'm using a temporary tripod account until Jimmy gets his act together and finishes moving his server (and our accounts).
Cheers,
Preston

Intel Celeron 1.3 Ghrz 512MB Ram NVIDIA GeForceFX 5200 128MB