If you are looking for fun songs to help teach your students the alphabet, letter names, letter sounds, and even sight words, check out Have Fun Teaching.
I have several students who just start singing in class. They are in kindergarten or first grade, and while they are still mastering letter sounds, they are able to sing out lines of text like, "Lately I've been, I've been losing sleep..." While I'm sure they have little idea of what the lyrics from pop songs mean, imagine if that type of automaticity could be achieved for letter names, letter sounds, and even for spelling sight words!
Here are just a few of Have Fun Teaching's videos:
What Do the Letters Say? (What Does the Fox Say Parody)
Letter F Song
The "Are" Song