can also use the d70s flash to trigger the sb800 wirelessly set the sb800 to SU-4 mode (by holding in the select button for 2 secs, then move right and press select then move down to SU-4 and press select, then hold select for another 2 secs). Then take a shot with the d70s with the inbuilt flash on and should also trigger the sb800, however if using TTL on the inbuilt flash may trigger the sb-800 too early, may want to consider switching cam to manual flash. As roti prata said this is all in the nikon manuals, the sb800 manual is good at addressing this.
