Advanced Twitter Feed Integration allows you to easily customise your twitter feed with widgets and shortcodes.
Here is the settings panel of Advanced Twitter Feed Integration, specifically where you add your twitter api keys.
This is an example of how to embed short codes into your WordPress pages, or how to embed into a php template page.
Here is an example of how to use the plugin as a widget and its options.
This shows the two different types of Twitter feed active in the footer Widget area.