I apologise if this has already been done. I have not been a member for long. This is my personal favourite, sung to the tune of Dean Martin's "That's Amore". Sung by West Ham fans to Bobby Zamora.
When the ball hits the goal,
It's not Shearer or Cole,
It's Zamora.

The response, by Chelsea fans....
When the ball hits your head,
And you're sat in row Z,
That's Zamora.

Liverpool fans sang about Manchester United

So light up the fire,
And let the Mancs burn,
Throw in they're shirts,
They're all made of turd,
They can't kick a ball,
They're just a dream team,
It's life or it's death,
They dive and they scream

[edited as breaks the basic rules]

Liverpool fans about Manchester United and Chelsea


Build a bonfire, build a bonfire,
Then put the Mancs on top,
Put Chelsea in the middle,
And set fire to the f*****g lot

Liverpool fans about Manchester United.


If I had the wings of a sparrow,
If I had the ass of a crow,
I'd fly over Old Trafford tomorrow,
And s**t on the b*****ds below

He's tall,  He's s**te,  He should of stayed a white,  Berbatov, Berbatov.

Same old tottenham always cheating, Same old arsenal always winning!

Fill up yer car,  So we can buy Kaka,  Fill up yer car,  So we can buy Kaka....

Walk on walk ooooon,
With no hope in your heart,
Cause you'll never win the league,
You'll neeever win the league,
Walk on

All round the fields of Anfield Road,
Where once we watched the king Kenny play,
We had Heighway was on the wing,
We had dreams and songs to sing,
Of the glory round the fields of Anfield Road.

Outside the Paisley Gates,
I heard a Kopite calling
Paisley they have taken you away,
But you led the great eleven
Back in Rome in seventy seven
And the Redmen are still playing the same way

Repeat Chorus

F*ck Off Chelsea FC,
You ain't got no history,
Five European Cup's and 18 leagues,
That's what we call history....

He's so fast, he's so cool he's s**t-hot with the ball
And he plays for us, he's Arsenal.

He destroys and he toys and he shoots and he scores
And he's forever ours, he's Arsenal.

Arshavin (go higher as per chorus) he.... Plays to win,
And he's forever ours, he's Arsenal.

Arshaviiiin, Arshaviiiin, Arshaviiiin, Arshaviiiin, Arshaviiiin, Arshaviiiin,
He's Arsenal!

Da-da daaaa, da-da daaaa, da-da daaaa, da-da daaaa, da-da daaaa, da-da daaaa,
He's Arsenal!

Stamford Bridge is falling down, falling down, falling down, Stamford Bridge is falling down, poor old Chelsea.

Build it up with red and white, red and white, red and white, build it up with red and white, poor old Chelsea

All around the Fields of Old Trafford,
Where once we heard the Man UTD fans sing,
Now its all gone quiet,
Cause the pool ran riot
Now theres silence round the fields of Old Trafford...

Debt-free, wherever we may be,
We're gonna' buy everyone we see,
And we don't give a ***k about the transfer fee,
'Cos we are the wealthy CFC. (Mr. Chelsea)