Lots of good comments here, thanks all:
-sizing: I need to reduce the spacing and font size so the thing fits on the screen better, especially vertically.
-mac packing: when the time comes, I will look into it, or ask for help (I don't have a mac).
-alef: tell me more about the tabs thing you mentioned. is there a screen shot?
-at the appropriate times, the JOIN button changes into a DROPOUT button.
-the player list will be on the brackets page I think. I might need a slightly more general name for that than "Brackets". Any ideas? Something more specific than "Information".
-diane got me thinking about making things simpler, and said something about the toolbar being the most useful thing. Does it belong on the first page with all possible buttons, i.e. join/dropout, create/open/start. Someone could detach the toolbar, minimize the main window, and just use that. When a new tourney is announced, the tourney number could be displayed on that bar. For a non-TD, that might be all they see: "Tourney: 345 JOIN".
-cekerr gave me a couple other ideas, but I think they will wait for a next release. Mostly it's a help guide popup that indicates to a newbie what the next logical step would be. They could turn it off.