I’m catching up… Here are the most interesting icon resources. You can use these sets both for commercial and private projects (as they say in their disclosures) – but to be on the safe side: check the license agreement again. This list is growing constantly – so drop by again soon. Please comment if you found more resources which are free for both commercial & private use.

• Iconbuffet – the community site with a lot of very creative icon sets (101 free sets now and growing every week) – my first visit!
• Silk Set – the famous and ubiquitously used set from Marc James is still one of the best (over 700 icons).
• Mint Set same author, different set- just marvellous.
• Tango Project – a huge resource for beautiful icons – for almost anything you can think of.
• The Iconmaster – artistic and fun.Take a look especially at Mondrian!
• The Notebook iconset from Manuela Hoffmann is a true hit.Very special!
• Toolbar Icons from Matt Ball.Highly recommendable.
• Everaldo Coelho produced a beautiful KDE Crystal Clear Set.Wonderful, not only for KDE…
• My fellow countrymen, the widely known Bartelme shares a beauiful shopping cart icon with the world.
• Deziner Folio delivered the free Aqua Gloss Set for private and commercial projects.
• Web 2.0 Buttons 3D-style you’ll find on Utom Box for free download and usage.
• Liquidicity gives you 165 free to use vector icons – so you can alter them in Illustrator for your needs – handy!
• The guys from Turbomilk give away some very nice & funny icons (just to mention them if you use it in public)
• InterfaceLift provides the fanatic with some nice icons (searchable for platform and other parameters)
• Sweetie is a nifty and as the name suggests sweet set of 182 icons in the base set and 37 icons in the web-communication set.
• Iconshock is the right place for all Vista icon freaks. Sign up for free and exchange with your buddies. You can use them in commercial and private projects.