I've got a Nikon D80 and have invested in a rather tasty 50mm Macro Lens, some extension tubes for anything really small, and a rather costly flash kit, also made by Nikon which consists of 2 independent, remote flash units both controlled through the camera menu!
I'm saving up for a macro lens for my camera - I got some macro rings/extension tubes which are okay, but the depth of field is nightmarishly small, I've had a few good results but it helps if the animal stays still. I wouldn't even bother trying to get a photo of the snakes close up, they're just too fast.
The lighting in those shots is spot on, so well worth the cost