Hi Pete -
It's easy. At the very top of this page click on your name (it probably says "Welcome, pedablue"...click on "pedablue").
In the page that opens click the box on the right that says "Edit Gallery Block".
You'll now see a page that gives you all sorts of options for customizing how your page appears. But if you look on the left, there's a column that lists other available options. Under the black box that says "My Settings" click "Edit Profile".
At the bottom of that page is the section where you can add your camera equipment to your profile. Conveniently enough, they called it "Camera Equipment"
Voila! Go get 'em