In Excel 2007, I am trying to apply conditional formatting based on a formula
which basically says "if a1 in sheet1 contains a number greater than 10, make
b1 in sheet2 red."

Firstly, I see that you Excel doesn't like using references to other
worksheets for conditional formatting criteria. I have tried creating a
named range and also copied the cells into the same worksheet (so they are
now linked) but it doesn't seem to like any of my attempts! I am probably
not using the right formula.

Any tips, advice and help would be most appreciated.