The official Delphi 64-bit Compiler Sneak Preview is now available at: http://www.embarcadero.com/products/delphi/64-bit.
You can watch a video with David I that shows the new compiler and gives an introduction to 64-bit and some tips for Delphi developers.
You can also fill out a form to get more information on the 64-bit compiler as it becomes available and to apply for the beta so you can try out the new compiler for yourself. Current registered users of Delphi XE and RAD Studio XE will get priority access (meaning they got to the front of the list that we will be adding to the beta). We'll add non-XE users as space is available.
Here's what the invite email looks like.
Hope you enjoy the preview and let me know if you have any questions.