Changing URLs and how to redirect from old to new site.

The primary focus of my blog have changed as a result of reader involvement. So, now I want to change my domain name–i.e., from http://example.com/blog2 to http://example.com/blog2. Once I made the change, if it’s possible, then I would like to redirect readers to the new site when they search for the old. Can anyone give you some guidelines as to how to accomplish this?

Thanks