How to Write a Song - WikiHow

How to Write a Song - WikiHow

This looked interesting.

I wish it was more instrument-oriented and had more about chord progressions, however.

While here be sure to check out the "Music" Category - this had all kinds of even more interesting musical how-to's. Sure you want to learn how to spin your drumsticks. Sure you want to learn how to "jump on an electric guitar."
But, seriously, there's "how to compose", and how to buy, play, and take care of a wide assortment of musical instruments. And more of musical interest.