Yes it is possible now with the upgrade to version 4.0 of the Wii system menu but the drawback is that you have to download them off of the Wii Shop Channel with points because of right now that's the only way and there is no wad manger out yet to let you install it onto the SD card yet(except if you count the one as part of the update in the Wii Shop Channel).
what brand and type of card si in your wii?
I swapped mine with the 8gb Sandisk MicroSDHC in my MP3 player and all the stuff I have installed works just fine. Well not 100% fine, I can not install wads from the 8gb card.. but can move them and run them after I install to the wii.
My SD card is a Kingston 1GB. It works fine for everything, even playing wiistore bought channels off of the card, but not ones I have installed via wad manager.
does the type of wad matter? I have tried VC, and wiiware channels so far to no avail (unless they are officially downloaded from the store)
Are you on 4.0?
Yes. Wouldn't I have to be to even be trying this?
4.0U here with full HBC and everything.
Don't bother installing those WADS lol.
I'm on 4.0u and i can install All kinds of WADs from my SD card using Wad Manager v1.1 and i can go to the system settings and move all VCs, Wiiware and Channel that i made using Wadder. i have a 2GB Kingston Mini SD inside a Kingston adapter
to get VC/WW to run off the SD card you need to run IOS60 found here
wehackwii / News - System Menu v4
@drops a lot of SDHC cards still arent supported by Wadmanager or HBC yet... I have the same problem with my 16GB HC card.. I can run anything from the card but cant run or install from either HBC or WadManager
And like Name13013 said, YOU CAN NOT install straight to the SD Card, you have to install it to the wii then xfer to the card. Wadmanager doesnt support SD install yet