When my kids were little, I sang them these songs almost every night. True, I changed the words a bit to make the songs my own, but these were the tunes and words they were based off of. Great memories.
I highly recommend the Alphabet song to teach kids the letter sounds. It truly helped my kids (2 of which had speech problems).
You can purchase these at www.BarbaraMilne.com. (I am not compensated for saying that... I just love her stuff).