Right, Sonixx. I think that's the only way to tell that's nonspecific to which software you're using. If there is one waveform on a track, then its mono. If there are two waveforms in a track, then its a stereo track.
As far as how to toggle between stereo and mono track properties in Acid 6, I'm not sure either. I've never used Acid so I dont know its interface.
Normally, there is a button/switch that you click to toggle between mono and strereo. If you hover your mouse pointer over some of the buttons on a track, hopefully the tool tips will tell you which one controls mono/stereo.
As far as application and when to use stereo tracks versus mono tracks, there aren't a whole lot of times when I'll use a stereo track in a multitrack project. Most of the time, its best to record a mono track and then use the track's panning control to set where the track sits in the stereo field.
The exception would be if you've mixed down a separate mix (like a drum kit submix) and want to preserve the panning of that submix.
Or, maybe you have a stereo source that you're recording from, like an effects box, a stereo microphone, or a line-level source like a CD player.
And the most obvious use for a stereo track would be if you've mixed down your project to a stereo .wav file, and load it into its own project for pre-mastering kinds of tasks. You definitely want to preserve the stereo field.