In between working on very early stages of our SC2 project, my team has also been working to wrap up our Command and Conquer 3 conversion. One of our latest updates includes a lengthy article about the texturing workflow we used throughout the project, and the 200+ textures made for it. Keep in mind this is not specifically about Starcraft 2, and the spec/normal map area will not be the same as SC2...but the general idea of how I texture, how I save time on the normal map and so on is universal.
Hopefully someone finds this helpful. :)
Once I get into doing art for our SC2 project, I'll probably be doing some new more specific tutorials up.
If you have any questions about texturing in general, post below and I'll do my best to help. I won't be much use for anything specific to SC2 yet though (plus there already are a few tutorials on the basics of model exporting/etc.).