Red Fly also went into more detail about the storyline of the game in a recent press release, since the DS version is a prequel to the Wii title. Both will cover different parts of the Mushroom Men's history, with Rise of the Fungi detailing a time when they first got their special abilities. The Bolete tribe must stave off attacks from hostile insects and other creatures, until the Amanitas Empire becomes an even bigger threat to their survival. Mushroom Men fighting amongst Mushroom Men ultimately leads to the Spore Wars, which are covered in the Wii game.
We really like the idea of one game's story leading into another's in such a short period of time (as in, you won't have to wait long between releases). While we're still not sure when the Wii game will follow, you can expect it in November or December if Red Fly sticks to the original plan.