Preloader ‘replaces’ the systemmenu (it’s not really replaced, its main.dol is just renamed) with a simple loader which allows you to automatically load the HBC, a .dol you can install from SD or the systemmenu. It also allows you to use simple patches on the systemmenu.

Warning: This homebrew application will brick your Wii if you misuse it!

Changes:

– added SDHC support
– added a new option to the “return to” setting: “return to: autoboot”
– changed FAT code to only mount/read from SD
– fixed a bug where enabled autoboot overwrote the “return to preloader” setting
– removed netcode, online update check, online update code
– The installer now get the IOS version the System menu uses from its TMD and if the version is 60 or higher applies the ES_DIVerify patch

Thanks to http://www.tehskeen.com/forums/showthread.php?threadid=14340 for the news.

http://wiibrew.org/wiki/Preloader