For those of us who like customization of standard programs, here’s a way to have a background for Windows Explorer toolbars. To get this, add the following string value in the registry:
 

Hive:	HKEY_CURRENT_USER
Key:	Software\Microsoft\Internet Explorer\Toolbar
Name:	BackBitmapShell
Type:	REG_SZ (String value)
Value:	the name and location of the bitmap file you want to use for your background (e.g., c:\windows\zapotec.bmp)

ENJOY!