In music school, I had to learn to read in seven clefs. This allowed me to transpose at sight, i.e., to read and play a piece instantly in a different key from the one it was written in.
But I have just discovered http://www.freehandmusic.com , which sells legal downloads of sheet music. Once you buy a file, you can ask your computer to transpose the printed music for you, and even to play it aloud so you can learn it by ear.
So save your educational dollars, people: you don't need to learn to read music anymore. And the only clef we need is the one in Superman's chin.