Forecasts that a federal hiring freeze will hit Washington and other outposts of the bureaucracy on Jan. 20 have terrified thousands of people in government, and outsiders who want in.

There is mass confusion over when, how and with whom the new administration will fill thousands of political jobs available to it and what the new team will do to the Senior Executive Service. A partial hiring freeze imposed earlier this year by the Carter administration already has whittled the federal work force by about 35,000 bodies. To complicate matters there are projections that as many as 70,000 federal employes may pull the plug in January to cash in on a retiree cost-of-living benefit. All of this, the reality and rumor, has contributed to nail-biting in this company town where 350,000 answer the factory whistle of the U.S. Government.

Still, it is an ill wind (or rumor) that blows no good. Freeze threats and administration changes have been a god send for publications and outfits that specialize in probing the entrails of the bureaucracy and telling people -- for a price -- where the jobs are and where to get them. Some of the information services are so good that the government subscribes to them to find out what it is doing.

Two primary beneficiaries of the uncertain job picture are Virginia-based companies that regularly publish lists of job openings here and around the country. For the benefit of readers who want to invest a few bucks in insiders' news sheets, and reference material beneficial to people in and out of government, here is a list of the services, what they do and what they cost. First, for job-hunters:

Federal Research Service: It publishes a biweekly listing of thousands of federal job openings. Like its competitor, the tabloid-format Federal Jobs Inc., it gives guidance to job hunters and news items of interest to people in government, and those wanting in it. Federal Research Service sells subscriptions (six issues for $21, or a full year, 26 issues, for $78). The address is P.O. Box 1059, Vienna, Va., Zip 22180. The FRS telephone number is 703-281-0200. Federal Jobs Inc., sells six issues of its service for $20, or a 12-month (25-issue) subscription for $70. Address is P.O. Box 1438, Leesburg, Va. 22075. The telephone is (703) 471-1417.

Once you find out where the federal jobs are, the next step is to find out where the people who do the hiring work. To fill that gap there is the Federal Employment Directory. It is a guidebook to the location of 200 federal personnel offices, along with their telephone numbers. Single copies are $5.75 plus 70 cents postage. Address is Department RP, P.O. Box 34740, Bethesda, Md. 20034. Telephone is (301) 533-3031.

Once in government, or retired from it, many people feel the need to keep tabs on what is happening in their agency, on Capitol Hill and at the White House. Oldest and most popular publication, particularly for people outside metro Washington, is the Federal Employees News Digest. It is edited by veteran bureaucracy-watcher Joseph Young, former federal columnist for The Washington Star. First-class subscriptions for one-year are $22. The Digest also published an annual almanac which lists data on government ranging from pay scales and retirement rules to benefit changes affecting workers. It costs $2.75. Address for both is P.O. Box 457, Merrifield, Va., 22116. Telephone is (703) 533-3031.

Federal Personnel Guide also puts out a desk-reference guide for personnel personnel with organization tables, promotion, pay and retirement data. Price for the 1981 edition will be $2.25 including postage. Address is P.O. Box 274, Washington, D.C. 20044. Telephone (703) 532-1635.

Federal Times: A popular weekly tabloid newspaper aimed at government workers and retirees. Although specializing in news, the Times also has regular listings of Senior Executive Service job openings. Price for a 25-week subscription is $11.50. Address is 475 School St. SW, zip 22024. 2Telephone is (202) 554-7274.

Federal Executive Telephone Directory: Looking for the private number of the president's chief of staff, or the head of the German desk at the state department? Their numbers, plus the office numbers of thousands of key federal officials are in the directory, which is updated every couple of months for subscribers. Yearly subscription price is about $96. Put out by Carroll Publishing Company, 1058 Thomas Jefferson St. NW, Zip 20007. Telephone (202) 333-8620. Good hunting!