My daughter is a recent college graduate about to move to Philadelphia to start a job. Her job will be in the suburbs, but she wants to live downtown. She doesn't know anyone and has never been to the city except to interview. How should she go about finding a roommate? How will she find a building that is also home to other young adults? Are there any specific places she should look?
I have a special pit of loathing reserved in my heart for "Jewish Mother" stereotypes. Now that I've received three questions in a row from mothers of 20-somethings, I've had to spend a lot of time figuring out how to avoid descending into that pit. Here's the thing, Serial Dating , Matchmaking Mom  and Housing Help — I actually totally respect where you're coming from. Maybe it's my own three years of motherhood catching up with me (or my 33 years of daughterhood reflected through that lens), but I'm glad that you're all coming to me. In part, I'm glad because you're asking good questions that show sensitivity to the concerns of 20-somethings, and in part because I'm hoping you're coming to me instead of bugging your daughters with your concerns.
Unlike the dating questions where it's nice but, ultimately, optional if your children date or not, your daughter will definitely need a place to live when she arrives in Philadelphia. Downtown, or, as we call it here, "Center City," is the place to be for young people. I agree that she'll likely have a better social life living in Center City than in the suburbs (bearing in mind that I am particularly anti-suburbs).
If your daughter hasn't already checked Craigslist, that ought to be her first stop. Despite the obvious discomfort with any website that has been in the news followed by the word "killer," that site is where most people I know find apartments and roommates. Additionally, the website for Hillel's Grad Network  (the content of which is either written or approved solely by me) has a well-utilized classifieds section, including roommate/housing posts. We also have a rental guide  featuring the properties and services of our sponsors.
If your daughter wants to live in a high-rise (often called a "doorman building"), she should find a time to come visit, walk into the various buildings she passes and talk to the rental managers. I'm partial to the Rittenhouse Square and Fitler Square areas, as well as Graduate Hospital further south (where I live, but which does not contain any high-rises). Many young professionals also live in the Art Museum area, Washington Square and other neighborhoods, too.
Some buildings that cater exclusively to young adults actually offer roommate matching services, and that could be one of the first questions she asks a management company. In addition to the previously mentioned Grad Network classifieds, I would suggest that your daughter use her online social networks to post something on Facebook like, "Does anyone know someone in Philadelphia who might know someone looking for a rooomate?" It's amazing what posts like that can yield, and then she won't feel so completely out of her element if there's some third-degree connection with someone else living here.
Using any of these approaches, I'm sure she'll find a roommate and an apartment that will be, if not wonderful, then at least satisfactory for her first year here. She should plan to sign only a one-year lease. Next spring, she can reevaluate her living situation with the benefit of knowing the city as an insider.
Along with housing, she should also start perusing the websites of local organizations catering to Jewish young adults so that she has a sense of what else awaits her when she arrives. Good luck to her in her search, and good luck to you in letting her find her own way.