This probably isn't the kind of advice you were looking for, but it's usually best to re-write your ETL in SSIS directly rather that attempt to migrate DTS to SSIS.
There is an upgrade package option, but bear in mind that some tasks are not touched by the upgrade process, such as ActiveX scripts. Note that this is not much better when going from SSIS 2005 to SSIS 2008 +.
In general, your process should be upgrade DTS, test test test, understand what it did, test test, re-write the bits that don't work any more, test, and deploy.
However, you may not have to upgrade DTS at all if you can install the backward-compatability pack for SQL 2008. Check http://technet.microsoft.com/en-us/library/cc768544(v=sql.100).aspx for more details.
Good luck ! 🙂
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