Hi there,
My understanding is that until the D2h and iTTL, no Nikon flash/bodies had built-in remote wireless capability.
You had to had a little device called SU-4, where the remote flash had to be plugged... I assume that using your F80 built-in flash as a master, and a Su-4 + SB600 as slave should work, but I have never tried this combo myself, you'd better call up Nikon to check this point.
In the iTTL compatible components (namey D70, D70s, D2H, D2Hs, D2X, SB600 and SB800 - not sure about D50), the built-in flash or a SB800 has to be used as master, while either an SB600 or SB800 should be used as slave.
Regards,
Bernard