So you were hoping to transfer your Monster Hunter 3 Ultimate save files between your 3DS and Wii U? Bad news fellow because that transfer utility is not yet available.
Both the 3DS “Monster Hunter 3 Ultimate Data Transfer Program” and the Wii U “Monster Hunter 3 Ultimate Packet Relay Tools for Nintendo 3DS” should have been released on the eShop yesterday but so far they are missing.
Yuri Araujo, Capcom’s associate online/community specialist apologized for the delay on Capcom-Unity forums. The post also mentioned that the tools should be up shortly but did not relay an estimated time or day.
Until the feature becomes available, you can play Monster Hunter 3 Ultimate on your 3DS or Wii U; you just can’t play on Wii U if you want your progress from both to carry over.