TurnFlash

From NirSoft:

Many Web sites today use the Macromedia Flash component for creating animated ads. These ads consumes additional bandwidth and sometimes even slow down your computer. Unfortunately, Internet Explorer doesn't provide a simple way to disable the Flash component. Furthermore, if you refuse to install the Flash component, Internet Explorer will constantly ask you to install Flash in each time that you enter into a Web page that contains a Flash object. This utility allows you to easily disable and enable the Flash component in Internet Explorer browser (Version 5.00 and above). When you disable flash with this utility, all new windows in Internet Explorer will be opened without using the Flash component. The disabling of Flash doesn't affect the windows that are already opened. While the Flash Component is disabled, Internet Explorer will not ask you to download and install it. However, the disabling of the Flash component might cause a script error in some Web pages. Be aware that in Windows NT, 2000 and XP, this utility will not work if you don't have permission to write to the Registry keys of Internet Explorer.