Nintendo is preparing another round of maintenance for their services. The first maintenance will start tonight around 3 am EST and will affect the Pokemon Black and White versions.

From Tuesday, March 26, 2013 12:00 AM – Tuesday, March 26, 2013 6:00 PM Pacific Time

Affected Services:

  • Nintendo DS
    • Network Services
      • Pokémon Black Version
        Pokémon White Version
        Pokémon Black Version 2
        Pokémon White Version 2

From Monday, March 25, 2013 8:00 PM – Monday, March 25, 2013 9:00 PM Pacific Time

Affected Services:

  • Wii U
    • Match Making, Ranking, etc.
      • Monster Hunter™ 3 Ultimate
      • Monster Hunter 3 Ultimate Packet Relay Tools for Nintendo 3DS

From Monday, March 25, 2013 7:00 PM – Monday, March 25, 2013 8:00 PM Pacific Time

Affected Services:

  • Wii U
    • Match Making, Ranking, etc.
      • Fist of the North Star®: Ken’s Rage 2

From Monday, March 25, 2013 6:00 PM – Monday, March 25, 2013 8:00 PM Pacific Time

Affected Services:

  • Wii U
    • Match Making, Ranking, etc.
      • Sonic & All-Stars Racing Transformed

From Monday, March 25, 2013 12:00 PM – Monday, March 25, 2013 6:00 PM Pacific Time

Affected Services:

  • Wii U
    • Nintendo eShop
  • Nintendo 3DS
    • Nintendo eShop
  • Wii
    • Wii Shopping Channel
  • Nintendo DS
    • Nintendo DSi Shop

Link