Speaking of DTS package portability, we use the SQL Server Client Network Utility (cliconfg.exe, installed with Windows) to create an "alias" for our DEV/TEST/PROD SQL Servers on all servers and workstations. For example, the alias we use is "CorporateSqlServer01", and on DEV servers and developer workstations it points to our DEV SQL Server; on TEST servers it points to our TEST SQL Server; and on PROD servers it points to our PROD SQL Server.

This has been a great help to us for deploying and migrating applications as well as DTS packages because the connection string never has to change:

"Data Source=CorporateSqlServer01; Initial Catalog=our_app_database; Integrated Security=SSPI"

Using the same concept, we create aliases for the file servers and what-nots in the HOSTS file, so UNC paths can be \\localhost\share or \\CorporateFileServer01\share and so forth. Again, so code and DTS packages can be migrated from server to server regardless of their DEV/TEST/PROD environment. Similarly, you can create a HOSTS alias for CorporateStateServer01, for example, that points to your ASP.NET state server (if you use one).