Checking if a key is held down at startup?

MyAccess project uses a small function to determine who's logged on when the
app is started. I'd like to add an option to allow the user to type in who
they are, in case they are logged in at home.

I'd like to implement this by having them hold down the option key at
startup. However, I can't seem to find an appropriate event for this. If I
put something in my onStartup, how do I check the keys from inside it?

Maury