Right first things first, soldering gun? I hope you're not using a plummers solder gun, they're really not a good idea for guitar electronics, they use a soldier with acid in it which ends up corroding electronic components.
As for wiring up a kill switch its pretty easy. If you've got an on/on switch connect the pickup output to one outer lug, ground to the other outer lug and connect the middle lug to the output jack. This way one way will connect the amp to the pickup and the other throw will connect the amp to ground (rather than connecting it to nothing which is the same as putting a lead in your amp with no guitar on it i.e. it'll buzz like mad!).
Hope this is helpful.
i wouldn't sugest to break the connection. a safer way to do it is gettin one of those on-off switches, wire the output of the guitar to one lug, and ground to the other lug. that way you wont have 'pops'.
thanks guys! no i am not using a plumber grade soldering iron, i've got a decent quality electronics grade one. both these responses sound great! i'm going to try Robert's idea first since i already have my old 3 way switch laying around. but if it makes bad popping noises then i'll switch to an on/off switch. thanks again!