Nice, some remarks:
The dark-yellow/orange as background of the swirl looks a bit weird... the colors don't really match, it seems. There is also a conflict of perspective, as the original is 3D, and the swirl isn't leading a bit out of the picture, while the entrance to the tent does.
The small one (with much less visibility by the way, so it matters less), looks a bit 'full' now, with text stuffed all over it -- there isn't any empty space left anymore.
I do think it's a good try though, but maybe in the end some different approach turns out to be nicer. I know the gnome and openoffice.org splashscreens are quite nicely done, but they are quite different too... I myself am completely inadaquate for artwork, so don't take my advices too seriously
Anyway, two issues I forgot:
1) It's essential that you provide your work under the GPL, as the original is. Please make an explicit statement to that effect ("I hereby license these images I made under the terms of the GPL. Those images [copy] 2004 Your-name-here]")
2) Size of those images isn't hardcoded in HTML, if it turns out to be better to be able to make them a little bit larger, that's possible. You should minimize it though, and the small one cannot be wider than it is now.
