In the video below I quickly run through the basics of Soundboard, from Ambrosia Software (makers of WireTap Studio and Snapz Pro, but they've made Mac apps and games for years). It's just what you'd think: a series of buttons tied to sounds, just like you'd see at a radio station for live broadcasting.
But Soundboard brings the drag-and-drop ease of desktop computing to the table, and adds several small features that add up. Namely: quick editing and loop controls. Plus, you can route your audio using Soundflower, or just play what you want through speakers. Given the number of crank calls I made as a kid, I'm glad this wasn't around.
Soundboard normally sells for $29, but there's a free trial and you get 25% off if you're a WireTap owner. Also, Ambrosia is encouraging Sound Byte users to switch over with a $19 deal for registered owners of that application. If you've ever wanted a live radio show like Dingo and the Baby, then Soundboard may be just what you need.
Incidentally, the screencast above was made using the excellent site, Screenr.com. If the video won't play on an iPhone, just click here for the Screenr page.