It's a migration. We have a migration wizard that will take your DTS packages and migrate them to SSIS. The thing you have to remember is that SSIS is not a minor upgrade to DTS. It's a re-write to make SSIS super scalable and have great performance and functionality. The good thing is that we still ship the DTS 2000 runtime in certain versions of SQL Server 2005 so you can continue to run your DTS packages even as part of a SSIS workflow.''
Tom Rizzo summed it up rather well in the quote above, there is no upgrade for DTS to SSIS, and my preferred approach when upgrading SQL Server 2000 to 2005 is to leave your DTS packages alone until you have time or new requirements that mean you just write some new SSIS packages and throw the DTS packages away.
