Moving swap partitions is easy, however I do have a couple of questions. With 1.5GB of RAM are you even getting into the swap? If not, swap performance isn't all that important. However, if you are I have a suggestion. Create a swap partition on each drive and balance them by setting them all to the same priority in your fstab (e.g. set them all to "pri=1" in your mount options in your /etc/fstab). Either that or stripe the drives and create the swap on the stripe set (not sure which would be faster). I assume that all drives are of roughly the same performace.
But if you did just want to move your existing swap, it's just as easy to just create a new one on the new drive and change your fstab. Something like:
# swapoff /dev/hda2
# fdisk /dev/hdb (create swap partition)
# mkswap /dev/hdb1
edit /etc/fstab to reflect the new swap partition, or add the new swap partition
# swapon -a
How large it should be sort of depends on how the system is utilized (of course there are some basic rules of thumb for minimums etc). For more on swap file priorities:
http://voidmain.is-a-geek.net/man/?mode ... §ion=2
Just make sure if you want them to be balanced, you use the same priority number on all of them.
EDIT: just found another little blurb that might explain it a little better:
http://www.xenotime.net/linux/doc/swap-mini-howto.txt