In the situation I'm in I installed the RTM without the registration key and was told that this would be OK if I could stand the naggs from Microsoft over the fact that the RTM was not yet registered. I was told that at the close of 30 days I would need to re-arm the RTM for another 30 days and that I could do this 3 times for a total of 120 day. Based on my install date of August 21st I should only have to re-arm twice before I get my hands on my "official" paid version of the product. I just didn't want to go to the trouble of reinstalling a bunch of apps and moving a bunch of files to my new machine and then finding out - oops you can't register RTM.
On that note..... Assuming that I can use the retail key on the RTM where (How) do I enter the key?