Goto the HD makers support website for details on your topic. They offer alot of hints/tips/guide best suited for the HD model installed plus any s/w required. If you didn't get such with your new HD, that's a good place to start. Look for a install guide or the FAQ related topic, alot of users ask tthe same question.
I suggest, use CS(cable select) on the HDs. When asked partition the new HD into maybe 80gb each(1/2 of available space) to better control the HD or simply use it all. I find it also better to deal with the new HD by itself in order not to harm the orginal HD, thus disconnect old HD, make new HD(solo) and then do what you have to. Hope this helps....
good luck -----Willy
Stupid question - but I've recently bought and installed a 160g secondary drive onto my computer (running with Windows XP).
All good - its being picked up by dos and in the device manager - but I have no idea how to go about formatting it.
Help would be much appreciated