Here in the UK there are MANY more advertisements for PS2 and X-Box. Where I am the shops are putting the X-Box and PS2 versions of Soul Calibur 2 at the front of their stores, and even the tv advert only shows theose versions, "forgetting" to put the GameCube version there as well. Even then though, the GC version sold the most!
Up 400% is a great start, I don't think that it's outselling X-Box yet though but it's definitely a start! Even the news that Argos and Dixons are restocking GameCube is promising for Nintendo coming up to the Christmas period!