Because you are calling it OIS I will assume you are Navy? I think its ODS now and here are the dates, sent out in the last fast facts (its suppose to be in collums, but it was in chart format...just rearrange it from one collumn to three to correlate class number with start date and end date):
ODS Dates:
CLASS #
08010
08020
08030
08040
08050
08060
08070
08080
08090
08100
08110
FY08
Convening Date
8-Oct-07
19-Nov-07
7-Jan-08
4-Feb-08
10-Mar-08
14-Apr-08
19-May-08
23-Jun-08
28-Jul-08
1-Sep-08
15-Sep-08
Graduation Date
9-Nov-07
21-Dec-07
8-Feb-08
7-Mar-08
11-Apr-08
16-May-08
20-Jun-08
25-Jul-08
29-Aug-08
3-Oct-08
17-Oct-08