Umm I don't really like your sig that much,,,
They're just user bars, Banners outclass them...
Ok I downloaded it by clicking on download on Devaintart.com
It doesn't matter which package you download, it's still a Gimp brush.
Ok after downloading,it showed up as a zipped folder.
I right clicked it and clicked on "extratc all". The extraction wizard popped up and I saw all the the brushes. I selected all of them and did Ctrl+C(copy) and I went to the Gimp brushes folder Ctrl+V(paste).Then I opened up Gimp 2.6 and then I saw all the new brushes.
Sorry for the typos (darn this Wii!) and I use Windows, not Mac, sorry..