Excel 2007 :: Adding Feedback Message Based On Cell Value?

Using Excel from Office 2007, and WinXP Pro OS

I have a spreadsheet which contains 2 drop down pick lists in Field1 and Field2.

Code:
FIELD1 | FIELD2 | FIELD3
--------------------------------------------
In Cell A2, I have this set in Data > Data Validation:

Allow: List
Source: =CatList

If the user selects a value from the CatList range, then the drop-down options in Field2 are updated accordingly.

In Cell B2, I have this set in Data > Data Validation:

Allow: List
Source: =INDIRECT(A2)

The Ranges are as follows:

Code:
Cat1 | Cat2 | Cat3
---------------------------------------------
Cheese | Hat | Square
Trees | Cat | Circle
Bees | Sat | Triangle
Knees | Mat | Rectangle
Apologies | Bat | Octagon

I'd really like to be able to add a message into FIELD3, which is based on the value in Cat2

e.g. using pseudocode, something like:

If Field2 value = "Apologies" then put this message in Field3: "This requires approval from A"
elseif Field2 value = "Triangle" then put this message in Field3: "This requires approval from XYZ"
elseif Feidl2 value = "Bat" then put this message in Field3: "This does not require approval"

Basically this is for an access form, and I need to be able to add a feedback message to field3 based on what's in Field2.

I thought about using the INDIRECT option to add messages but I can't see how I'd do it. Maybe VB would do it, but I don't know it well enough.