giving connection strings in variables,expression

I have created a SSIS package in the visual studio i used connection manager for all my tasks but now I want to use variables for my server connections and local paths etc.. , rather than using connection manager to avoid migration problem from server to server.
Can we use expressions also for this purpose then kindly show me a example.

I want to use this package as a scheduled job in sql server.

And i want to know various deployment methods available for a package in sql server.




Thanks,
Gautham.R

Read about creating configuration files with SSIS package where you can specify the connection parameter at runtime.