Hi Kathleen, you are to be commended for planning so far ahead! This will ensure you have the perfect holiday that you envision for this special wedding anniversary.
Disney releases different specials at different times, and they often change from year to year. Check in on this webpage which will tell you about
upcoming specials. If you are a AAA member you can ask them to keep you up to date on specials.
So while I do not know what is coming up for 2012, I do have some good news for you: you can go ahead and make a Disney reservation (online or call 407-WDISNEY) and if a better price or special comes up, they can modify your existing reservation to give you the better deal! I do recommend this, because the sooner you book, the better the chance that you will get the type of accommodation you want. March is a very busy time and some types of rooms/resorts will sell out.
If a special anniversary dinner is in the works, make sure to book that exactly 180 days in advance of the date you want it - just call 40-WDW-DINE.
Have a magical time with your family!