I came across a really awesome icon resource awhile back, but never got a chance to write anything about it. If you’re a web designer or developer who always has use for quality icons — especially ones with GPL or similar licenses — this is the website for you. It’s essentially a search engine for icons. Everything about this website rocks, especially their logo:
Not only can you filter by license type and image size, you can also download both the PNG and ICO versions on a black, white, or transparent background. You can edit the tags for any icon and, if after all that you still can’t find the icon that’s right for you, you can opt to purchase a custom icon design.
The website doesn’t have a massive selection of icons to choose from yet, but you should find something relevant to what you’re looking for. If not, you can always design it and submit it yourself.