If you don’t have the skills or the time to create original icons for your website you can find plenty on the web. iconfinder is a search engine to search for icons. Two other icon search sites are www.iconlook.com and iconlet.com
This site allows you to download a set of 140 free icons available in 4 different sizes
If you are interested in ASP.net icons you will find 300 free icons at this site.
A great collection of icons from from dryicons.com
A collection of 700 free mini web icons from FAMFAM FAM
Free greyscale icons.
400 free icons in PNG format
Free glass icons
Vista icons from Jm Art Studio
Crystal Clear Collection
128 Free icons – Function
Scratch style icons
1000 Free Icons from FatCow
130 Iphone Icons
And finally, a few web icon tutorials.
Tutorial on creating Vista and Aqua buttons
Tutorial on how to create Windows Vista buttons.