Is there a way (I think there is) whereby if I type a certain letter in a cell, it can alter the colour formatting of the cell to represent what I have typed. E.g, I type a '+' and it turns red, I type a '-' it turns green.

You need to use conditional formatting to do that, simple enough if you read the help files

Aye.

conditional formatting

Just done a quick search for a tutorial, have a look here:

http://en.allexperts.com/q/Excel-1059/Change-cell-color-based.htm

done. excellent, thanks.