Did you know that Visual Studio 2005 ships with a library of standard windows bitmaps, cursors, icons and metafiles which can be freely used in your windows and web applications? It contains Windows, Office, and Visual Studio icons that are licensed for reuse.
You can find it here: C:\Program Files\Microsoft Visual Studio 8\Common7\VS2005ImageLibrary\VS2005ImageLibrary.zip
In addition the .ico files are in multi icon format with the 16×16, 32×32, 48×48 images (and color depth 256, 16bpp, 24bpp) contained in a single file.