Darc, here's the quote from a Gamespot article about Spaceworld this year. It was mentioned in the Pilotwings story. Here's the article text:
"GameSpot has learned that Factor 5, the development team behind the Rogue Squadron and Rogue Leader games for the Nintendo 64 and GameCube, is indeed working on a new Pilotwings game for the GameCube. While Nintendo has no official comment, the game is expected to be shown in some form either at E3 or at Nintendo's Space World conference, which will be held in August.
We'll post more as it becomes available."
Some people are saying it was just a mental hiccup on Gamespot's part, though. I'm guessing we'll know if it's true or not soon enough, one way or another. If Nintendo starts saying "wait until Spaceworld" when being asked questions at E3, that will certainly solidify it.