HI i went to Berlin in June, i absolutely love this city and the shopping is fantastic just head down to the ka'dam. They have all the great high street shops such as zara, mango etc as well as the designers. A great book that is relative;y cheap which i found invaluable is the Belitz poket guide book of Berlin £5. The hostel i stayed in was the Meininger, which is very centrally located just a 5 min walk away from checkpoint charlie. However if you are looking for a party hostel i hear that the generator is excellent. These hostels can all be booked on travelpunk
and i have found that the rates are somewhat cheaper than just going to the hostel and booking. Arriving at Schonefield is pretty easy. Dont forget to do the New Berlin walking tour, they give you a 6 hour tour for free, they also do a barcrawl for about 10 euros, which i thouroughly recommend!
Have fun in Berlin