To execute and edit DTS packages in SQL 2008:
1) Download and install the ‘Microsoft SQL Server 2005 Backward Compatibility Components’ (Yes, they are labeled as being for 2005, but they will work with 2008 R2) from : http://www.microsoft.com/download/en/details.aspx?DisplayLang=en&id=16177
2) To open the DTS designer, install ‘Microsoft SQL Server 2000 DTS Designer Components’ from http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=11988
3) I had to edit the PATH environment variable so that the path for the installed SQL 2000 components come before the 2008 ones. I found a post at: http://blogs.msdn.com/b/ramoji/archive/2008/10/16/how-to-open-dts-packages-in-sql-server-2008.aspx