I found a great little program a few months ago that is like finding the mother of all modding gold mines. Its called Filter Forge.

What is Filter Forge 3.0?

Filter Forge is a versatile Stand Alone program and Photoshop plugin which lets both novice and expert users create a wide variety of realistic and abstract textures and effects. Users can take instant advantage of over 8430 free community-created filters in the online filter library, or create their own filters in the visual filter editor by assembling them from components such as blurs, gradients, color adjustments, noises, distortions, or blends – without writing a single line of code.

http://www.filterforge.com/filters/
----------

Its a small program that lets you create thousands and thousands of amazing textures which all tile seamlessly and only take less than 10 seconds to make. For the free versions you just have a look at the online library, click the botton and it imports to Filter Forge automatically, then from there you can change parameters such as colour, amount of detail, etc. you can make normal maps and bumpmaps of textures and chose from thousands of variations of those textures and filters.

Im using the 30 Day trial and it doesnt even ask you for any information at all, not even your name, you just download it (60 megs) and away you go. I've used it to make all my textures for my mod "Moar Kontent" (WIP) and I cant stop raving about this. This is definately an awsome program for you modders out there.

I've used Filterforge as well for Oblivion modding. Even if you don't use the program itself (which either costs money or is a 30 day demo), the site has a lot of great textures that come with top quality normal maps (most of them, some are screwed up). Especially the 'techno' category has some great textures that can be used for Dwemer type stuff.

Theres also a few free small packs of a couple of types of textures and those are free to use forever. I only realy got it so that I could make 1024x1024 textures.