Ann Landers, it seems, has decided to dispense more than advice in her daily column. Now she solicits contributions for her pet political cause.

In her July 23 column, she urged readers to ''pick up a pen today and write a check to Handgun Control for $25, $35, $50, $100 or more.'' After giving the address of that political lobby, she then added that her check ''went out today.''

What Landers failed to tell her readers was that she herself sits on the board of directors of Handgun Control, Inc. (according to the 1987 edition of Public Interest Profiles). In short, she was secretly using her column (which newspapers pay her to write) to promote the financial and political interests of her own organization.

Such conduct is both unprofessional and unethical. Newspaper columnists are presumably journalists -- not political fund-raisers. It is simply incredible that Landers was allowed by your newspaper to run what amounted to a fund-raising letter as one of her columns.

A few years ago, there was an uproar when it was revealed that conservative columnist George Will had helped coach Ronald Reagan for his debates with Jimmy Carter. Yet Will's actions look tame beside those of Landers. Will, at least, never used his column to solicit funds for Reagan's campaign committee.

What is even worse than this clear conflict of interest, however, is how Landers distorted the facts in her column to create support for her position. Landers printed a lengthy letter that berated the National Rifle Association and claimed that guns are useless in providing protection to honest people.

Despite the rhetoric in her column, guns remain one of the most effective -- and popular -- tools that honest people have to fight crime. Polls show that 13 million Americans live in households where a family member has had to use a gun in self-defense and that around 600,000 Americans a year use handguns to defend themselves from criminals. And a 1985 inmate survey for the National Institute of Justice revealed that most convicts (58 percent) think that ''a store owner who is known to keep a gun on the premises is not going to get robbed very often.''

In short, guns in the hands of law-abiding citizens are highly effective. And Ann Landers' uninformed harangues won't change that fact.

Landers presumably wants people to face the criminals alone -- without any means of defense except a prayer and a plea for mercy. Perhaps she thinks that if we submit to the criminals, then the murderers, rapists and muggers will be nice to us.

It's a free country; if she wants to believe that, she can. But she has no right to use her column to enlist financial support for her hidden agenda. If she continues to do so, perhaps you will have the courtesy to provide truth-in-labeling and rename her column ''Advice for the Gun-Lorn.''

-- Joe Friend The writer is executive director of the Citizens Committee for the Right to Keep and Bear Arms.