My goto tool for B&B anywhere in Canada is BBCanada.com. It has a huge range of B&Bs all over the country (77 in Quebec City alone - BedAndBreakfastWorld has 7, two of which are motels). They are divided by region, and often down to different areas of the same city. I've never had a bad experience with any B&B I've booked through them, and many of the them have been remarkable.
Different B&Bs have different amounts of information on the site. Most have photos, some have breakfast menus, some let you book online, most have links to the establishment's own website. I never worry about certifications - I just look at the pictures and the description and make my choice.
B&B are a great alternative to hotels. You are not always going to get the comfort level of a hotel (though you will much of the time) and you won't get all the ameneties and the 24hr service, but instead you will get to meet interesting people, find out interesting things about where you are visiting, and get a lot closer to the 'local' experience.