There are a number of ways to go about this. One way would be to enter the date 8/1/2013
manually in the first cell (say A1
for example's sake) and then in B1
type the following formula (and then drag it across):
=DATE(YEAR(A1),MONTH(A1)+1,1)
Since you only want to see month and year, you can format accordingly using the different custom date formats available.
The format you're looking for is YY-Mmm
.