I haven't seen this posted here yet, so I made a complete pinout for the Wii's WiFi module. It has 6 primary data lines, as we know, and 2 unused GPIO pins. It communicates via SDIO - 4 data lines, 1 clock line, and 1 command line. The 1.8v is not an input, but more of an output for reference (or something like that). This information is based on the datasheet for the main IC: BCM4318.