working with cells

[trey]

i have a drop down menu that i want to link up with a
cell from another sheet within the workbook and populate
a cell within the same sheet as my drop down menu...

i also have another question... i have a cell for a loan
amount... i want to create an action where if the loan
amount goes say over $200,000 it triggers an action from
within another cell in the worksheet..
example: $200,000 then .25 appears in the other cell..
and if the amount is less then then " o " or nothing
appears...
plz advse..
trey