There are many ABC games available online through sites like PBS KIDS and Fisher-Price. These are free flash games developed for babies and older children.
Parents can find online alphabet games for their kids to play through many educational websites, and commercial sites geared towards children. For instance, PBS KIDS has a number of different ABC games based on popular children's programs. Just visit the PBS KIDS page, scroll down and click on "All Games". On the next page, scroll down and click on "All Topics" in the side menu. On that next page, look for "ABC Games" and click on it to go to the alphabet games for kids.