Yes, that will be possible. Unless changed in the final release (which I doubt), the installation routine is very much similar to Vista and W7, and you can select a destination drive on which to install the OS.
When Vista Beta came out I never installed or reviewed it.
I did take a peek at W7 and then uninstalled whatever I had of it. Then purchased the upgrade when W7 became available as I was coming from Vista Home Premium OEM version.
In W7 Forums there seems to be a lot of discussions on partitioning going on and have read a few threads. My experience in that category is next to zero so now I am more curious with W8 Beta coming and how to and where to install it without messing with W7.
If you have any tuts or threads that I might get a handle on I would be most thankful for your input.
The easiest way to do this is download Winrar, it will act as your .iso handler. Open the .iso with WinRAR and double clik the Sources folder, scroll down the contents till you find setup.exe. Double clik the file and WinRAR will extract all the necessary files to temp and the Windows install will begin. This file always asks you what partition you want to install to. I have used this method for years...