Around this September, I'm going to Buenos Aires. I'll stay for around 3 months and go to a local high school. I'll live like any other Porteno kid, except I don't know that much ...
Do most people in Buenos Aires speak a little English?
I'm going on a trip to Buenos Aires, and although I speak a little Spanish, I don't speak it well. Will it be fairly easy for me to get around speaking English?
Most Argentineans speak basic British English. The language is taught since fourth grade in all elementary public schools. Even the schools in the shanty-towns have English teachers. For real.
You will do just fine. Make sure you grab a "castellano" dictionary before you go down though... the Spanish from Mexico and Spain will NOT be sufficient. :)
Alguien
I live in Buenos Aires, and yes, I can tell you a lot of people here speak English.
In the most touristic areas it's a given, but also in many other parts of the country you'll probably find Argentines eager to practice their language skills with you, since most schools give at least basic English lessons.
Still, I would suggest you to keep learning and trying to improve your Spanish. Not only it will help you to communicate better, but it will also improve your travelling experience. Good luck!