The power of the press can't be underestimated. A strong publicity program is one of the factors in a successful marketing program. Consistent, newsy and interesting press releases lets the media know about your company and can establish you as an expert in your field. That means when a reporter is working on a story that's relevant to your industry they'll call you for an interview.
How do you establish such a working relationship with the press? Make sure your press releases aren't hard sell or are written like an advertisement. You might be extremely interested in the release of your new product but is it news worthy? How will your product make the readers' of the newspaper or publication, lives easier or more productive. Think benefits to the market not attributes of your product or company.
Send press releases out on a regular schedule every 3 or 4 weeks, but keep them news worthy.