First, just find a shortcut on your desktop and right-click on it and select Properties. On most, you'll have an option to "Change Icon".
I've found there are any number of .exe and .dll files that have icons in the Windows and Windows sub-folder directories. You just have to use the "Browse" button after selecting "Change Icon" and click on an .exe file or .dll file. Of course, shell32.dll is probably the largest icon archive in Windows.
As for free icons, they are all over the net. Here's one:
I have Windows XP Pro, SP3.
Now when I want to change icons and get a bigger choice I use the file "shell32.dll." Are there other icon files included in my version of Windows?
Can I get icon files off of the internet, and if so, where?