Wii Shop and IOS51 installer is a very quick modification of PatchMii modified by Muzer that does one thing: It installs the new IOS51 and Wii Shop Channel from the 23 Oct Updates, without installing the patches to all the other IOSes. This means that as long as you didn’t update, you can now install this to use the Wii Shop Channel but keep all the benefits of not having the update.

http://www.wiibrew.org/wiki/Wii_Shop_and_IOS51_installer