You can go uptown to Columbia University and watch from the location where Barack Obama spent some of his undergraduate years. My Columbia Journalism School roommate informs me that Columbia will be holding an outside screening to simulate the National Mall experience. From the Columbia website:
Presidential Inauguration Viewing
Date: January 20, 2009 from 11:00 am to 2:00 pm EST
Location: Columbia University Morningside Campus Low Memorial Library, Plaza
President Lee C. Bollinger invites the Columbia University community to join together in watching the historic Presidential Inauguration of Barack Obama (CC'83).
While other notable Columbians Theodore and Franklin Roosevelt and Gen. Dwight Eisenhower have served in the nation's highest office, this non-partisan event will mark the swearing-in of the first Columbia graduate as President of the United States.
A "Jumbo Tron" screen will show the inauguration live on Low Library Plaza beginning at approximately 11:00 a.m.
The downtown kids at New York University will have warm and cozy environs for watching. New York University is screening the noon ceremony at the following locations: