I'm writing a monologue/imaginative spoken task/analysis on the representation of guilt and conscience in the play Macbeth, for the Banquo's ghost,...

This appears to be an interesting assignment. I can
certainly point you in the right direction of the quotes that you need, but as far as
the actual response you write, you are going to have to think very carefully yourself
about what you do and how you do it. From the question you have been given, it seems as
if you need to be creative above all, so try and think of different ways of completing
this assignment rather than just writing an essay.

The
dagger scene comes in Act II scene 1, and is part of one of Macbeth's soliloquies that
is very important to study. The appearance of the dagger directly relates to the
internal conflict going on inside of Macbeth, and the themes of guilt and conscience.
Note how this soliloquy starts:

readability="26">

Is this a dagger, which I see before
me,

The handle toward my hand? Come, let me clutch
thee:--

I have thee not, and yet I see thee
still.

Art thou not, fatal vision,
sensible

To feeling, as to sight? or art thou
but

A dagger of the mind, a false
creation,

Proceeding from the heat-oppressed
brain?

Note how conscience is
refered to in the way that Macbeth seeks to interpret the dagger, which is a symbol of
murder and his guilt. His conscience is clearly showing the path that lays before
him.

The scene containing Banquo's ghost occurs in Act III
scene 4, which is when Macbeth is the only person able to see the figure of Banquo's
dead body seated at the banquet table. A good quote would be when he addresses the
ghost:

Why,
what care I? If thou canst nod, speak too.--

If
charnel-houses and our graves must send

Those that we bury,
back, our monuments

Shall be the maws of
kites.

Here we see Macbeth's
guilt and fear and his conscience working altogether to oppose him. Having coldly
organised for Banquo's murder, he is now tormented by his ghost, which is a visible
symbol of his conscience refusing to be ignored.