If you already use keynote, I'd recommend at least checking out keynotekungfu.com. It's a tool kit for wireframing in keynote. It's not quite as easy to use a

If you already use keynote, I'd recommend at least checking out keynotekungfu.com. It's a tool kit for wireframing in keynote. It's not quite as easy to use as gomockingbird.com but it has more customization. I don't like how gomockingbird doesn't even allow for formatting of text. KeynoteKungFu is only $12 so it's not too expensive to test out.