Secure Pipes is a menu bar application that enables you to easily manage SSH tunnels without having to worry about the SSH commands to start them or have to restart them if they go down. Configuration for Local Forwards, Remote Forwards, and SOCKS proxies (dynamic forwarding) are supported.
The software is merely a management user interface wrapper on OS X's existing SSH binaries and stays out of the way of any existing SSH configuration (for example, it maintains it's own separate known hosts). This app is not in the app store because it contains a number of features not allowed by the app store's sandboxing requirement (such as binding to privileged port numbers, changing network configuration, etc).