As originally reported on Serebii.net, a magazine scan that recently appeared on a Japanese forum has mentioned the names of three new Pokémon Mystery Dungeon games for Nintendo WiiWare. While unconfirmed and with no details on the games beyond the names themselves, this is interesting enough to share.
Translated from the scan, the three games have been called "Pokémon Mystery Dungeon: Keep Going! Blazing Adventure Squad", "Pokémon Mystery Dungeon: Let's Go! Stormy Adventure Squad!", and "Pokémon Mystery Dungeon: Go For It! Light Adventure Squad".
If/when more solid information is revealed on these titles we'll let you know.
UPDATED June 20th: As an update, Nintendo has officially confirmed these three games, as shown here with the official title art on the Pokemon website:
I don't think there's any further information, but these games will be coming to the Wii for definite now.