Excel 2003 - Capitalisation question

[Belgarath75]

I was wondering if there is a way to set up a cell to format the text that is entered into it in the following way

The Cat Sat On The Mat

I know that there is the =PROPER(cell) function, but this seems to be to correct it after the event, and what i am trying to do is to force this to happen as users fill in the cells

Ideally i would like to find a way to do this without VBA's

Hope that makes sense

Belegarath75