I have never heard it pronounced any other way than G(eye) Forks! Heaven knows what his friends called him.

The sanitised version of the poem in the website listed by Bill is:

Remember, remember the fifth of November,
Gunpowder treason and plot.
We see no reason
Why gunpowder treason
Should ever be forgot!

the version that I grew up with was:

Remember, Remember the fifth of November
The terrible gunpowder plot
A naughty young fella
Got caught in a celler
and ... cor what a hiding he got!


(Trans: a good hiding is a beating)