Update: Nintendo UK's PR dept, Cake, have given us official clarification on the Zelda situation - Twilight Princess will be reaching stores this year in Europe with a TBC date.
The reason for the difference in Wii and GameCube release dates being a priority to manufacture as many discs a possible, but Wii being a bigger focus.
Stick with C3 for future updates!
Quick News: According to reports from NeoGAF, the GameCube version of the latest Zelda tale, Twilight Princess will be heading to Europe in "the middle of December". Previous reports had suggested that the title would only reach American shores exclusively, however now seems to be featuring global retail.
Stick with C3 for future updates. Again thanks to Mr. Ashcroft for the tip.