How to make a rough metal material ?

I have been working with Blender for a long time, yet I have never had to deal with materials as I have been using the app for modeling and animation for video games mostly.
Now it’s time to make an animated intro and I need to make a rough metallic material, similar to one that they used in Transformers (the Cube) minus all those fancy hieroglyphs.
Maybe something similar to this: http://www.filterforge.com/filters/7273-v8.jpg but slightly more grittier.
Can anybody help me out and sort of guide me through the process, please?

http://www.cogfilms.com/tutorials/Cog_s_BSoD/Introduction_to_Materials_and_Procedural_Textures.pdf

Colin has you covered. This is a great start to learnin materials. Some tips from me, metal needs reflections to look good, these can be raytraced, envmapped, white planes with emit turned up, hdri images, or actual geometry in your scene. The next thing to look for is scratches, best achieved with a hand painted texture IMO.

cool stuff, thanks! any hints on where to get acceptable HDRI images?

http://www.hdrlabs.com/news/index.php Here are some, they are all over the net but very hard to find sometimes. I have been stockpiling them for years, http://www.debevec.org/probes/ is where I got my first ones. I’d send some of mine to you but I am not sure of licensing issues with the ones I have. Also good ones are spherical, in .hdr format and usually like 30-45 megabytes each. You can get some really nice metal using them with raytracing.