It is a TCP server running on the Wii that listens on port 8080 by default that will run any binary that is sent to it. Both DOL and ELF executables are supported. There is no IP address display in the Wii part, yet.
There is currently some progress on writing a windows gui to do the loading by dasda, while there is a cli tool for posix. The Windows-transfer tool will be released tomorrow (April 9th) due to lack of testing. Dasda 12:10, 9 April 2008 (PDT)
You currently need libogc cvs and bushing's socket patch in the sf.net patchtracker to compile this yourself. Precompiled binaries will maybe be released by me once this patch is in the cvs. Source code