The academic year starts Sunday Aug. 31, 2008 for first through third years (4th years are in the states doing their electives). As a first year, you are required to get to Israel in mid-August for a mandatory 2-wk orientation. There is no Ulpan class before, but you could of course come early and take one. The school offers Ulpan once/twice a week (depending on your fluency level; more for beginner, less for advanced) after classes. Some students prefer to have their own private tutor but they have to pay for that.
Personally, I went to the hebrew classes at school for my first semester of my first year, but stopped simply because the time commitment was too much. The more hebrew you know, the better you can fit into Israeli society (even though the majority of the people you meet can speak English). In regards to the hospitals, certainly the majority of older patients do NOT speak English. They can speak anything from Hebrew, Russian, French, or other languages. The younger the people the more likely they speak Enlgish. I'm a second year and what I have seen is that unless you are extremely fluent in Hebrew, you will still have a difficult time in getting patient histories from those who speak Hebrew/broken Hebrew. Unless I have a translator with me, I will only do patient histories/physical examinations alone if the patient speaks English.