Choose a possible outlet for your work:
Option 1: The Directory Method
Option 2: The Database Method
Another option is to look for the scholarly conversations about your topic. To do that, search your topic in an interdisciplinary database. When you find some journals that are covering your subject area, use Google to find the journal's home page and instructions for authors.
The book reviews and oft-ignored "books received" lists that appear in most journals will give you a list of potential book publishers. Here's an example of a books received list.
Option 2: The Database (Library Catalog) Method
Option 3: Browse a Directory
Option 1: Google It!
For calls for papers and proposals, good old Google is probably your best bet; it should pick up most public announcements, often including professional organizations. Type in your subject area or your discipline along with calls for papers or calls for proposals.
Example search: biology and calls for papers or calls for proposals
Note: This search will also pick up calls for papers by journal editors/publishers.
Pay attention to the date the information was posted--unless you have a time machine.