For anyone rich enough to have bought \ lucky enough to be gifted the internet channel, speedtest.net has developed a Wii specific portal for their website. Feel free to browse the site on your computer but It's pretty neat to gauge your Wii's download \ upload speeds, ping and IP.
I found this after rearranging my router for optimal signal
Results for my Wii
Download : 3.40mbps
Upload : 0.35mbps
Ping : 40ms