I am an F1 student currently working full-time in a paid summer internship in Philadelphia. I am on CPT.
I am aware that I am liable for city, state, and federal income taxes. I am also aware that I am exempt from Social Security and Medicare taxes. However, am I required to file any tax forms now that I am earning taxable income? What other requirements am I supposed to fulfill in terms of taxes?

I hope someone can help me out! Thanks a lot.

You DEFINITELY will be required to file a federal (Form 1040NR) and Pennsylvania state tax return in January, 2013.

I BELIEVE Philadelphia requires you also file a city tax return, even though you probably will owe NO additional tax.