I noticed this question on the Office:Mac forum:

My daughter is headed to college this fall. I just got her a Mac because the college she is going to is a Mac campus...that is all they use. I would like to get her the Office 2011 for the Mac. I understand that the release date might be in 12/10 but it also might be later. Are we at a place where MS is on schedule with that or is it later? I would hate to get Office 08 if in 6 months, Office 11 comes out. Is their an upgrade policy regarding that or am I just buying two versions? I am sure others has this question as I had read that on here but didn't see any specific responses from the Mac Microsoft team. Thanks for your time.

We're still on track to release Office:Mac 2011 later this year.  I don't have a specific date to share yet, but I will the second I can.  We don't yet have an upgrade policy.  I'll share that when I can as well.  

Before buying Office:Mac at a retail store like the Apple Store, Best Buy, or Amazon.com, any college student should check with their institution.  Many colleges and universities offer Microsoft products, including Office:Mac, at a deeply discounted price.  (Likewise, if you're an employee of a large company, check around: you might find that your company takes part in Microsoft's Home Use Program, which also gives you a deeply discounted price for Microsoft applications.)  The student bookstore should know, and a departmental secretary will know too.  (In fact, make good friends with your departmental secretary: they know everything.)  

If your college doesn't offer such a deeply discounted rate, and if you don't have a need to buy Office at this split instant, you might want to wait to see if any good back-to-school deals come about.  I don't know what kinds of plans the various retail outlets have, but I've often seen good back-to-school deals in previous years.  Watch the ads in your Sunday newspaper.  I'm sure that good deals will also be noted by the various Mac news websites, too.