If so you'll probably install and then be sitting at the command prompt and asking yourself: Now how do I join the domain? Along with many other questions, like how to set a static IP or deploy AD as a role on the server. Check out the Server Core Installation Option of Windows Server "Longhorn" Step-By-Step Guide which has been updated for the Beta3 timeframe.
We've been running server core in production since Beta2 last year and unless you logon locally you wouldn't notice the difference between full server and server core. This is a good thing. :)