If you feel bored with the default icons set which comes with your application or if you use any dock apps like rocket/object docks, and want to match all the icons with your theme set, search for icons online with various sites mentioned in this post.These icon search engines provide free download of icons in various formats.
IconLook
This site seems to the best icon finder.
Various features available are tagcloud search, browse popular icons, random icons and filter with size.
The icon database is huge compared to others.
IconFinder
Here you have options to search with the help of Tagcloud, you can even choose the sizes of the icons.
IconsSearch
Size filtering option is present but the search results interface does seem attractive.
IconDB
This is an Ajax based search site. Search Interface looks awesome but no size filtering available.
You know better sites? Mention those in your comments…
