Download of MuteKey 1.0.2 for Mac was available from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The actual developer of this free Mac application is davechengapps. The program is included in System Tools. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
MuteKey allows you to mute and unmute your microphone with a global hotkey shortcut. There is a minimal MenuBar interface that shows you whether your mic is currently muted or not. The tool supports custom device selection so you can pick exactly which microphone you want to mute.
You may want to check out more Mac applications, such as Macfilink, Missing Sync for Palm Pre or PSPWare, which might be related to MuteKey.