Avanquest Connection Manager was previously a $30 worth application that recently went free. This piece of software is great, specially for laptop users who often have to move between home and office and use different net connections at different places. Avanquest Connection Manager lets you create different profiles on your PC or laptop for different connections that you might have - LAN at home and at office, Wifi etc. When you select a profile and apply it, it automatically re-configures all your network settings and applications like network printers so that you don't have to do it manually each time you switch networks.
Avanquest Connection Manager even lets you re-configure your installed applications based on the network you select. For example, you can configure your email client to retrieve mails only when you are using your ADSL connection and disable it when you are connected via your 3G network. Or you can configure your browser to use a different homepage depending upon the connection you are connected to. If you have more than one net connection on your computer, you will love this tool.