There is a very good town map tutorial by Larp just a few threads down the line. There are others as well, just use the search function as I don't remember titles exactly.
I was wondering how I could make buildings, using photoshop.
Here is one way to make buildings [Here] and if you just want some you can drop into a map and color to match what you are doing I made some [Here]. I would also search the guild for some key words and see what comes up... because there are many great examples made by other as well. (I second looking at the one done by Larp found here)