Usually all daycare centers have open house events every several months. It's a good idea to attend those open houses and do a comparison yourself. When your child is ready for the daycare, you can make an appointment with the supervisor and have a personal tour to the daycare you are interested in.
As Serge said, the waiting list for daycare is usually quite long. Many parents register their children to the daycare even before they are born.
Starting from this year, Ottawa started to use a centralized waiting list for licensed child care service. So you don't have to fill the registration form for each available daycare. You just need fill the form provided by the central system and submit it. Please go to the link below to find more information about this new system. http://www.ottawa.ca/city_services/childcare/index_en.shtml