Since you have migrated your packages it is safe to say that they are then SSIS packages and they are stored in the SQL Server.
Create a job, Create a new job step. Select SQL Server Integration Services package execution as the job step type.
For more info see 2005 BOL topic: How to: Run a Package Using a SQL Server Agent Job
David Lundell
Principal Consultant and Trainer
www.mutuallybeneficial.com