asterisk users - Aug 2004 - transferring call to another line

Hi,
    I just got my zaptel fxo cards working, and I want to be able to 
have someone call in on one line and access the other - I guess what I 
want to do is transfer(exten), but that is only for extensions - not 
channels which is what I want i guess.  I tried the Dial(Zap/2) but I 
think that's for ringing that line (fxs)?

thanks
Imran