Programs are held only at the Annual Conference. Please be aware that at the American Library Association, most programming for the annual conference is completed by membership committees who prepare the programs and have them approved at the prior annual conference. The best way to work with these groups is to investigate which ALA division, office, or round table fits closest with your presentation's subject matter. Then you would contact that division or office or round table for details on contributing to their program at the conference. Within ALA, these various departments focus on the different types of libraries or on specific aspects of librarianship. See this question for the lists of the ALA divisions, offices, and round tables that are on the ALA website.
Some of the ALA units send press releases announcing their calls for proposals of programs and presentations. The most recent such press releases have been collected at Delicious.com at
If you are an author and wish to participate in the Annual Conference, first contact your publisher, which may already be a longtime ALA Annual Conference exhibitor with a booth for scheduled author signings and presentations. If you work with a publisher where that is not the case, see the section Exhibiting/Arrange to Have Your Book Displayed at a Trade Show on ALA Library Fact Sheet 5 - Marketing to Libraries for some other options.