The ds wifi library has a new release and is now available from sourceforge. This will also be included with the soon to be available devkitPro Updater 1.3.5.

DSwifi 0.3a
The following items have been significantly improved or resolved since the 0.3 release (this is a rough list, mostly taken from a list of outstanding issues that have all been addressed now)

• gethostbyname no longer has problems with IP addresses
• wifi_lib_test tcp connection bug fixed
• getsockname/getpeername support have been added
• Internal TCP Error possibly causing loss of data fixed
• Better access to stats
• “keepalive” message to ensure AP connection remains open
• Improved syncookie implementation for more reliable incoming connections
• modified timeout code to use exponential backoff
• inet_addr support added
• TCP connection closing errors fixed
• TCP no longer loses data when rx buffer is filled (by remote host)
• Latency issue fixed, lib’s high pings are back down to normal.
• possible bug with recv not returning data it should is fixed
• Problem with DHCP should be fixed, it’s possible some routers still deny DHCP - if you have one that does this please let sgstair know
• Connect() now blocks, when socket is not in non-blocking mode
• select() support that should be sufficient for all applications is in
• TCP MSG_PEEK support added for recv();
• Shared key authentication!
• many TCP speedups and optimizations

Also, please see http://akkit.org/dswifi/ for some example projects, and links to the community and further information.