It sounds like you want to rent points from someone and have them transferred into your account.
I don't quite understand the 'expiring June '08" question. If this means you have someone with a June UY and you want to know if you could use those points, then the answer is probably not.
First, those points do not transfer into your August UY account. They would remain as June UY points.
2nd, if they are actually June 2006 points that were banked into a June 2007 UY, then they can't be transferred at all.
3rd, if they are june 2007 points, then they can be transferred, but you cannot bank them because June Use Year's 8-month expired Jan 31st. Transferred points can be banked only if they are still within banking windows. If MS allowed banking transferred points that were past their banking windows, that kind of defeats the purpose of a banking window in the first place.
Also, if the transferred points are a different use year than your own points, be aware you couldn't combine them directly with your points to make a reservation.
To make things simple, and to work best for you, it'd be a lot better if you found someone with an August Use Year and got points from them. Your next best thing is to get points from someone with a later use year than yours. For example, if someone transferred their Dec 2007 points to you, you could bank them into their 2008 use year (which goes 12/1/2008 thru 11/30/2009) and then use them for a 2009 reservation.
Hope this helps