libogc is a collection of low-level libraries for the GameCube and Wii. This collection of libraries was originally written by shagkur for the GameCube and has been developed over the past 6 years.

Changes:

Improved smb speed.
Increased default tcp window size to improve speed over internet.
remove casts from time conversion macros

Source: http://wiibrew.org/wiki/Main_Page

http://www.devkitpro.org/