One quick way (not kelly) is to look in your docs on the back of the Sign and Sail form. There are usually some numbers on the bottom. Often your cabin number is embedded within those number and may start with a "letter".
On Glory - 05-06-06
Sensation,Jubilee ,Maj.of the Seas,Conquest, Victory.
Also as others have posted try ordering yourself something from the gift services. I beleive to do this you have to go into the fun pass system, sign in as if you are filling out the pass but instead of clicking on the fun pass, click instead on gift services. Try to order something by clicking on the item then you'll go to another screen that has you booking number then under that it will either have gty (which won't tell you anything) or have the room assignment which is what you want. Don't order anything tho--(unless of course you want to <<BG>>>>) after you see that screen just log out or back out of it.