This can be done with custom formatting of cells.
If you don't understand how to create a custom number format read the
following site,
XL2003 How to create
http://office.microsoft.com/en-us/excel/HP051995001033.aspx?pid=CH010036911033
XL2007 How to create
http://office.microsoft.com/en-us/excel/HP012165031033.aspx?pid=CH100870371033
Once you understand how to create a custom format, keep reading.
The choice of colour readily accessed by name is limited [BLACK], [BLUE],
[CYAN], [GREEN], [MAGENTA], [RED], [WHITE], [YELLOW]. However, there is a
[COLOR n] option that opens up more choices.
Using GREEN, as below gives lime green and is difficult to read.
[Green]0;[Red]-0
Using [Color n], my opinion is the best available green shade is 10:
[Color10]0;[Red]-0
The above does nothing fancy in the way of formatting. Zero and positives
are green. Negative numbers are red. You may wish to use a different format
for your numbers (e.g. to pick of commas in thousands). The following will
do this:
[Color10]#,##0;[Red]-#,##0
This site will give you further help:
http://www.ozgrid.com/Excel/CustomFormats.htm
Run the following macro on a blank sheet to pick you n colour
Sub ListNColours()
'run in a blank sheet
On Error GoTo ListNColours_Exit
For i = 1 To 56
Range("A" & i) = i
Range("A" & i).Interior.ColorIndex = i
Next i
ListNColours_Exit:
End Sub