There are oodles of apps designed to let you share photos, but not so many that have an element which can cater for sounds too. I know about Audioboo, of course, but OverHeard takes the AudioBoo idea on a step or two, majoring on sound but with some neat additional features.
So, the basic idea is that you use OverHeard to capture something audible and then share it. Now your friends and family can get a real flavour of how good (or bad) little Sally's violin playing really is, or hear your friend tell their amusing stories, or listen to the sounds of the noisy market you are enjoying, or whatever.
You can tweak the sounds you've recorded, adding a range of effects to voices, inserting background noises and such. And of course there has to be a visual element too – you can add photos and tag friends. And yes, in case you were wondering, you can tweet and share stuff on Facebook.
Here's the thing, though. Have you ever said – "oh, I wish I'd taken a picture of that" just after something great had happened? Well, OverHeard actually records automatically, using its three minute buffer to give you a window from which to save and share what you just heard.