It looks like the 0.1alpha3 release of the Wii Twilight Hack now works with the internal SD slot. No USBGecko or other additional hardware needed.

There are 5 versions of the chainloader for the different regions and releases of the Wii console. Follow the instructions to unzip the right one to the correct directory on your SD Card, and then it’s as simple as copying your homebrew .elf file to the SD card’s root directory and starting up Zelda.

Twilight Hack 0.1alpha3- [via] Link