My first attempt was to fire up Acorn, great application, and edit the one I had. In the end I wasn't pleased with the results, due to my lack of skills with an otherwise fine piece of software.
Next I thought, I know I can do this in Visio in about two minutes, but being lazy like I am, decided against it.
Thought number three was the winner. Since I could do this in Visio I'd probably be able to bang it out in OmniGraffle, right? Well, not so fast. My Visio prowess doesn't translate to OmniGraffle. Hmmm....
Enter a Google search for "star shapes for omnigraffle", which produced a link to a script! Ah-ha!
I downloaded Peter McMasters Star Script, created a new folder in my FastScripts Scripts Folder, called OmniGraffle strangely enough, and dropped Star.scpt in place.
Here's where it gets scary. I switched back over to OmniGraffle, selected the FastScripts menu, located Star, and clicked...
It worked as advertised! Woo-hoo!
After I had the shape I was looking for I added a shadow, changed the fill, inserted some text, exported as .PNG, and did a bit of touchup in Acorn, and I had what I was after. A nice cheezy Web 2.0 Starburst!