Depends what you want. You don't need a boot manager - 2k/XP's boot loader will handle this. If you just install XP on the second drive, it will update the boot sector/boot.ini on the first drive and create a dual boot menu for you. However, this does mean that if anything happens to 2k boot sector/installation, the XP won't boot (ie, installations are not independent).
If you want them independent, disconnect the 2k drive while installing XP (it will then create a boot sector on its own drive). Once installed, reconnect 2k - you can then use a 3rd party boot manager like boot magic or partition magic's. I use one at
Or you could run bootcfg from XP recovery console or just edit the boot.ini file on the 2k drive to add an entry for XP (note - if you use either of these methods, you will also need to copy the ntldr & ntdetect.com files from the XP installation over the ones on the 2k (C

installation.
Boot.ini should look like:-
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINNT
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINNT="Microsoft Windows 2000 Server" /fastdetect
multi(0)disk(0)rdisk(1)partition(1)\WINDOWS="Microsoft Windows XP Professional" /fastdetect