You can use the SET parameter with DTEXEC

http://msdn.microsoft.com/en-us/library/ms162810.aspx

xp_cmdshell will need to be enabled.

Create variables in your packages. The use expressions in your package so that your destination and sources refer to you variables. Your variables will need to have defaults. Get the package running manually. Then you can use DTEXEC and set your variables at run-time.