I've used this song so many times. It's a kind of call-and-response song that's great to use with Year 1 or Year 2. Even Year 5 likes it!
You can see Michael Rosen performing it here. I love the way he performs poems and songs. He has these amazing eyes and is so dramatic:
I think Helen Oxenbury's pictures are brilliant too - I especially like the painted landscapes on the colour pages.