Say you're planning a targeted mailing to coincide with a promotional blitz in St. Louis, and you need all the zip codes within a 50-mile radius of the city. ZIP*Select (Melissa Data, 800-443-8834, $290; for PC compatibles) spits out all the zip codes within a specified radius of any city or county. It also breaks down the number of businesses, residences, and post-office boxes, and calculates the distance between zip codes.

ZIP*Select is by no means the only software designed to save you money or otherwise improve your next direct-mail effort. Among the choices:

* DataLift (Peoplesmith Software, 800-777-2460, $345; for PC compatibles) cleans up names and addresses and improves uniformity of mailing lists; puts names and addresses into standard upper- and lowercase.

* PostSaver (PostSaver Systems, 313-879-0550, $295; for PC compatibles) is a complete mail-management system with bar-coding capability. PostSaver Lite ($125) is for those who already have a management system but need a bar-coding utility.

* ZIP++ (Arc Tangent, 805-965-7277, $195; for PC compatibles with hard disk and CD-ROM) contains a national address database that is updated quarterly (for $195). It adds carrier routes to addresses and the "plus four" to zip codes, prints bar codes, and prepares reports required by the U.S. Postal Service to reap savings on carrier routes and bar codes.

* Mail Flow Planning System (U.S. Postal Service, 202-268-3917, free; for PC compatibles) gives an overview of Postal Service automation, explains bar codes and carrier routes, and calculates potential savings from a spreadsheet that you fill in with the volume and frequency of your mailings.

-- Michael P. Cronin