From Nintendo's official specs page (http://www.nintendo.com/techspecds)...
Wireless Communication: IEEE 802.11 and Nintendo's proprietary format; wireless range is 30 to 100 feet, depending on circumstances; multiple users can play multiplayer games using just one DS game card
This does not specify 802.11a, b, or g. However, as far as I know, the DS is only compatibly with B networks. If that's the case, I don't see why speeds of 11 mB/s can't be obtained.