ManageFlitter is a critically acclaimed set of Twitter Tools loved by over 1 million people. Unfollow, Follow, Twitter Search & Analytics.
Twitter is a great way to expand reach and a tool that allows you to manage your twitter in a more effective way is worth considering. This is one tool of many. There is a free option, but it is unclear what the limitations on that are. Also a number of difference packages to suit your budget.
See on manageflitter.com