From the MSDN article Migrating DTS Packages to Integration Services
Support for DTS in SQL Server 2008
DTS packages can still run as before when you have the SQL Server 2008
database engine installed. To accomplish this, you must have the
Microsoft SQL Server Backward Compatibility feature installed from the
SQL Server installation media or the Feature Pack Web page. This
installs the DTS runtime for SQL Server 2008, which works on 32-bit
platforms only.
If you perfom an in-place upgrade from SQL Server 2000 to SQL Server
2008, then all the DTS packages stored locally will be preserved as
DTS packages in SQL Server 2008. The upgrade process does not
automatically migrate DTS packages to the Integration Services format.
To edit the DTS packages, you must have the Microsoft SQL Server 2000
DTS Designer Component installed, which is part of the SQL Server 2005
Feature Pack and is a separate download from the Microsoft website.
You can manage your DTS packages from SQL Server Management Studio
under the Management à Legacy à Data Transformation Services node.
Here, you can open existing DTS packages stored on the file system or
in the msdb database, or add additional packages to the server by
clicking the Import button. New DTS packages cannot be created from
Management Studio, but old packages can be modified and renamed.