You've just hit the hardest part of the migration out of 2000, retiring DTS. I'd suggest a mixed approach. Run the Upgrade Adviser and let it scan your DTS packages. It will identify any that can simply be moved into SSIS. Move those. Change the connection strings on the others, leaving the 2000 server in place, as was previously suggested, and start a vigorous campaign to upgrade the remaining packages.

That's the plan we're implementing right now.