Whether you own either Pokemon Mystery Dungeon: Explorers of Time or Pokemon Mystery Dungeon: Explorers of Darkness, you can now recruit Burmy (Sandy Cloak), Butterfree and Beedrill - thanks to these new online missions! In addition, each recruited Pokemon will hand you a valuable item!
Burmy (Sandy Cloak) Online Mission
Burmy's Brown Gummi has been stolen by Garchomp! Retrieve it from the Mystifying Forest. A Ground Dust also awaits.
Butterfree Mission
Join Butterfree on an excursion through Spatial Rift. You'll also receive the Sky Dust.
Bedrill Mission
Beedrill craves an Oran Berry. Deliver it to Beedrill in Dark Crater to complete the mission and receive the Poison Dust.
Source:
http://www.pokemon.com/