Vowel Bat is a very catchy tune that teaches children what letters are considered the vowels. (Warning you may find yourself uncontrollably humming it during the day). The day I was using it in my class the two classes next door heard the song through the walls and by the end of the day children were singing it in the playground.
Vowel Boot Camp was also a firm favourite in my classroom.
When two vowels go walking is a great way to teach the phonetic sounds that two vowels make.
Do you any other ones???