This can be powerful means to conveying the nature of your organization and its services. Consider using a consultant for the initial design and layout. Today's desktop publishing tools can generate very interesting newsletters quite inexpensively. You can get your business in the newspaper by placing ads, writing a letter to the editor or working with a reporter to get a story written about your business. Advertising can get quite expensive.
Newspaper are often quite useful in giving advice about what and how to advertise.
Ironically, these are often forgotten in lieu of major newspapers, yet the neighborhood newspapers are often closest to the interests of the organization's stakeholders. Note, however, that many groups have strong groundrules against blatant advertising. When you join a group, always check with the moderator to understand what is appropriate. But think of how often you've actually noticed posters and bulletin boards yourself. Your best bet is to place the posters on bulletin boards and other places which your customers frequent, and always refresh your posters with new and colorful posters that will appear new to passers by.