Ithaca has very limited apartment availability. It actually only has a fraction of the available rental units when compared to the national average. For this reason, it is important to start your search as early as possible. If you accept a placement at Cornell and want to live off campus, you should start apartment hunting as soon as you've decided to attend.
You will be hard pressed to find a similarly sized town with a better public transit system than Ithaca. The TCAT system connects all major points in Ithaca, and provides a great means for commuting from an apartment to the University. It also connects to the surrounding county and is a provides a means for easily touring around to some of the surrounding country.
If you like live music, you'll enjoy the bustling music scene Ithaca is home to. The University also has many attractions worth visiting, including Cornell Plantations, which is a large botanical garden. There are several worthwhile waterfalls nearby the city that make for great day hikes. If you're just looking for a place to wet your whistle, head to one of the many Collegetown bars.