Here's a part of an interview with the President of RedOctane, Kai Huang:
Pro-G: What systems will gamers be able to venture online with? Anything planned for the Wii?
KH: There is online for the PS3 and Xbox 360. There won’t be online initially for the Wii, but we are working with Nintendo to see how we can get those features in.
Could this mean a downloadable patch that adds online support? I think it more likely means we're not getting online, unfortunately.