I have a SSIS package built in Business Intellegience Development Studio which have both source and destination database specified. Now I want to use some variables to param
There is a nice post here that details one way of doing this.
You will need to use a ConnectionManager and set the ConnectionString property of that from a Configuration Package.
The ConnectionString property is a fully qualified database connection string, like
Data Source=localhost;Initial Catalog=SSISConfig;Provider=SQLNCLI.1;Integrated Security=SSPI;Auto Translate=False;
There are a few gotchas and annoyances with using configuration packages so you may have to fiddle around a bit. I'd be more detailed but it has been about a year since I last worked on an SSIS project.
If you have any specific problems, please come back and comment about what you've hit. I'll try and refire the old memories.