Darkain has updated his DS Wi-Fi hacking page and offers this glumy prognosis:
I have also been in contact with several developers that are all exploring possible ideas of way to do bi-directional communication with the DS. As of now, we have only been have to do packet sniffing. I will be blunt on this one: I personally think at this time that we may not have a way to communicate with the DS on the Windows platform, and even on Linux, it may require the use of custom made drivers just for this purpose. Not only this, but only a few select cards will work with the current ideas we are playing around with.
Check his page for more detail. Obviously nothing was ever gauranteed and at the moment I still am optimistic that something will be worked out.
As I've noted (read: complained) in other places, it's not clear that there is full cooperation and disclosure amongst everyone working on the DS hacking efforts. Unfortunately people tend to get a little cliqueish about these things. There are many hands on the monster that is the DS hacking scene and I am not sure which of them is aware what the others are doing.
To be fair however, this is not true of everyone, Darkain and many others on gbadev's DSDev forum, Warp Pipe and sometimes #dsdev on EFNet have been very open about their progress. In any case, chin up!