Bootmii Booter is (just another) small (almost useless) program meant to be chosen as installed file in preloader. It boots the Bootmii IOS using a IOS_Reload. Using this as installed application makes it so you don't have to start the Homebrew Channel and then load bootmii.
Although this application won't hurt your wii in any way it still is buggy and might crash your wii.
Det1re's BootMii/IOS Launcher does the same, but does kill the function __IOS_LoadStartupIOS().