Right click the cells (or entire columns) that have dates in them. From the menu that appears, select Format Cells. In the Format Cells window that appears, select Custom and in the type box, type in the following:-
then click OK. In the formatted cell (or cells), if you type in, for example, 8/2010 the result will be August, 2010.
This gives you an idea of what can be done, so experiment with it in a blank sheet and change the formatting to suit yourself.
I hope that this helps.