Using the Homebrew Disc Loader, you can load homebrew programs from regular ISO9660 DVDs. It supports (sub)directories.

Changes:

Added support for meta.xml (name and long_description)
Added support for DISCINFO-file (see above)
Added eject- and retry-functions
Fixed issue with scrolling through a long list
Fixed issue where program crashed randomly due to a bug in memory allocation
Changed name to Homebrew Disc Loader

http://wiibrew.org/wiki/Homebrew_Disc_Loader