There is an interesting discussion about it here.
Jim from coffeecuppers.com had this to say:
Additionally, one of the posters to that thread thought that freezing a very short amount of time after roasting helped.The basic answer is
1. freezing retards staling, and very deep freezing (-40 C or F) eliminates it. Coffee in a home freezer stays fresh for at least a month.
2. it has to be done right, or its useless. The coffee has to be stored airtight and allowed to warmup completely before reopening the package. Otherwise one gets condensation, which is worse than staling. It is best if as little moisture laden air as possible is stored with the coffee, vacuum pack is best, wrapping tightly or storing in a filled to the stuffing point jar also work well. I use freezer or valve bags which I roll up tightly to expel the air, then seal. This works fairly well, and keeps the coffee fragrant for at least three weeks.
I havent really had time to try it out. I dont think that I have ever had enough coffee around for it to be worth trying ... especially with the new machine. I went through 250g just yesterday and today :o (No, relax; I had lots of people over!)
Interestingly, George Howell of Terroir Select Coffees in the US of A is now deep freezing greens. I believe that Howell is the man that convinced Daterra to invest in the Penta packaging system for their coffees ... basically if you buy a 24kg box of daterra sweet collection it has two 12kg sealed foil bags of green beans inside it! It would be interesting to buy some green, deep freeze some and keep some normally, then roast them and cup them head-to-head in a year.