Parents of toddlers everywhere, prepare yourselves. YouTube sensation and music teacher Ms. Rachel and her husband, Aron Accurso, will release their debut album, the 23-track "I'm So Happy," on Sept. 25.

"Music is such a wonderful way for people to bond, for parents to bond. I know from the minute my kids were born, we're singing to them," Ms. Rachel, whose real name is Rachel Griffin Accurso, said.