What software do people use to create vista style icons / images...? For example: The icon for readyboost (the clock with the flash drive) or something like that...?
Have a look for something called IconLover (yeah corny name) - but really useful if you are intending to do proper 32bit alpha blended icons. It also supports the multiple sizes vista requires. If memory serves me correctly a proper Vista Icon must have everything from a 256x256 size down to 16x16 size included in the one icon file.
No, not Photoshop!! The pros use vector apps, like Inkscape or <shudder>Illustrator. As mentioned, there are plenty of free collections available. Try www.smashingmagazine.com for a good start to your search.