apt and multiple cdroms

[Daniel Quinlan <daniel@netwise.net.au>]

hi,
  I've just got debian 2.0 on cd from lsl (http://www.lsl.com.au)
and main, contrib and non-free are on separate cdroms.

how do I setup apt to handle this?
my current sources.list is

deb file://cdrom/debian stable main
deb file://cdrom/debian stable contrib
deb file://cdrom/debian stable non-free
deb ftp://ftp.uwa.edu.au/mirrors/linux/debian stable main contrib non-free
deb ftp://ftp.uwa.edu.au/mirrors/linux/debian/non-US unstable non-US

but when I run 'apt-get update' I get an error on the two cd's which aren't
inserted.
if I run apt-get update three times with a different cd each time how will that
affect the package cache?

I get < 1k/s over my net link so using the cd's would be preferred 

thanks,

--
Daniel Quinlan                     daniel@netwise.net.au
Netwise Australia                  0417 677 377
"Engineering Network Solutions"