[Asterisk-Users] dialplan question - how to dial an * extension to get an outbound dialtone?

[Justin Richards]

First, please forgive me if this is a total newbie question, I've only
just begun to scratch the surface of asterisk.

I currently have a dialplan set up to let me dial a specific
extension, authenticate the user, then have * dial a hard
coded/programmed overseas number.  What I would like to do is set up
my dialplan to have an extension that offers up an outbound dialtone
allowing the authenticated user to dial their own number (be it
overseas, local etc).  Can someone point me in the right direction
with an example?  I'm assuming I need to use a variable but its not
clicking in my head yet how to actually read the incoming digits into
said variable. Thank you very much for your time!

Justin