Launch an app from within another (iPhone)

Question

Is it possible to launch any arbitrary iPhone application from within another app?, For example in my application if I want the user to push a button an

Answer 1

A side note regarding this topic...

There is a 50 request limit for protocols that are not registered.

In this discussion apple mention that for a specific version of an app you can only query the canOpenUrl a limited number of times and will fail after 50 calls for undeclared schemes. I've also seen that if the protocol is added once you have entered this failing state it will still fail.

Be aware of this, could be useful to someone.