having 2 optical (cd / dvd) drive in 1 computer, how to setup properly?

im thinking of getting a DVD drive for my new computer, i currently have:
a 20 gig and a 40 gig on 1 ide cable
a cd burner on the second ide cable

ive checked to make sure i have enuf cables and case space which is fine, but i have a question about the sound cable that goes from the cdrom to the sound card input, do i leave that in the cd writer or what do i do as im not really sure what this little cable is actually used for anyway...

what im thinking is it used for playing an audio cd directly or somethin like that?
and also where on my IDE cable would i put the DVD drive, on the end plug or the middle plug to avoid any problems with games not finding the cd drive that they were installed from?

another thing im concerned about is the heat from the drives and CPU, the system runs at about 34 degrees C and CPU at about 60 degrees C under load from seti@home, would i need a couple of case fans in the drive bay that i havce spare or should it not make too much difference overall to the temp?

I personaly never had any trouble with 2 drives (CDRW and DVD) on one IDE cable.
Also it doesn't matter wich connector you use.. as long as you set the MASTER / SLAVE jumpers on the drives..

I don't use the analog output to my soundcard, both drives allow digital output, wich I prefer...

You don't need to use the sound cable, and most soundcards have more then one analog CD input port (like a SB Live!)..

The heat may be a bit more tricky.. try to keep an empty slot between the DVD and CDRW, to allow some more air to travel between 'm.. (if possible) you could also add some more fans to ur system (chassis fan etc.)

One other thing to look at is your PSU (Power Suply Unit) is it of sufficient Wattage??

the power supply is a 350W, i had been considering drive bay fans for the spare slot, but the explanation makes everything simpler now which is good, the other problem is it will either be on top of the hard drive or under the writer, im thinking under the writer would be better as it wouldnt make as much heat as a 7200 rpm hard drive would