Regarding housing, I stayed at 1500 Locust Street during the WWW. Very well kept apartments--spacious and close to all of the team meetings and late night haunts of Wharton students. Possible drawbacks to keep in mind: apparently you need to tack on some additional time in the morning to wait for the elevators to finally arrive at your floor. This is typical of extremely large buildings, but for some reason this problem is worse at 1500 than at other building I have visited. Also, while we were there a fire alarm went off in the building at 4AM and lasted for 1/2 an hour. According to the student that we were staying with, this is not an uncommon occurrence. Just some food for thought.
Also, yes I was told that students living in rittenhouse area will share cabs in the morning. This may be preplanned, but I was also told that you might happen to run into fellow students during the morning rush, since so many people live in that area and there are a few prime places to catch cabs.
Regarding the new housing guide, it should be released by the April WW, but do keep in mind that the new reviews should not COMPLETELY change your mind if you perform some external due diligence. Just be aware that the rental rates have increased since the time the 2008 guide was published, so an apartment that is at the top of your price range might have been pushed into "unaffordable" range.