Mobile Educational tools or applications for children?

I got roped into being the new English teacher at the local Kindergarten. It is only one hour a week but the thought to teaching 75 kids to sing in English and basic phrases is scary!  I also really don’t have the time but just couldn’t bring myself to say no.

I remember writing about Skill Pill which was a business application learning service. But are there any other mobile educational learning applications?  For children or language learning?  If anyone knows of any – please let me know. If they save me or help me with my new duties I promise the biggest ever plug to whoever helps me – EVER!