I don't think it's worth the effort unless your system really needs this little tweak.
If you're constantly short of memory, better add memory.
If you want to do the tweak anyway, use the first partition on the 2nd disk for the page file.
If you use XP, you can have more than one pagefile. Keep your regular page file on C, but set it to a smaller amount perhaps. Set your 2nd page file on the 2nd disk. XP is supposed to be able to choose the most efficient page file to use (so MS claims).
Then there's the question of whether the 2nd hdd should be on the same IDE channel as the first hdd - that would depend on how many IDE channels you have, how many optical drives you have, and what you usually use the hdds and optical drives for .... Not worth the trouble.