Going July 2010. If making a booking at 11 month window in August will I be able to use 2011 points or shall I have to wait to start of next use year(Dec use year). Thanks
Use year has nothing to do with when you can make a reservation. All that matters are your 7 and 11 month windows. You need points to be available at the time of your trip, not at the time you call for a reservation.
The points for all use years are already in your account and available for use based on the date of stay. With a December use year, a July 2010 stay could use banked 2008, currrent 2009 (current = 12/1/09 to 11/30/10), borrowed 2010 points.
December use years can be difficult to understand at first. Take a look at the Understanding Use Year thread and make yourself some December use year "charts" like the example in the thread. It will soon become second nature to you.