For IT work, stay in Gachibowli, Madhapur, HITEC City or Kondapur. For heritage sightseeing around Charminar and the Old City, Abids or Charminar itself are closest. Banjara Hills and Jubilee Hills sit centrally between the two. Secunderabad is best if you're arriving by train.
October to February is the most comfortable, with mild days and cool evenings. Summers from March to May get very hot, often above 40°C, so plan sightseeing for early morning or evening.
Rajiv Gandhi International Airport is at Shamshabad, south-west of the city. It's well connected by expressway, but allow extra time if you're heading to the northern or eastern parts of the city.
Yes - Ramoji Film City, Hussain Sagar, the zoo and the city's museums make it one of the more family-friendly metros in India, and getting around is generally easier than in larger cities.
Hyderabadi biryani is the obvious one, along with haleem during Ramzan, Irani chai and Osmania biscuits at the city's old Irani cafes, and Deccan-style kebabs.