Want to raise a bilingual child. Should me and my wife speak different languages to our newborn right from the beginning?

The best time to pick up a second (or even third or fourth) language for a child is before the ages of five to six years old. It is regarded as a "peak period" where their language acquisition skills are at their best. They can easily pick up the different phonetic pronunciations (believed to be at their sharpest before 3 years old). Like you have mentioned, having you and your wife speak different language to your baby will help. Be consistent with who speaks which language and it will minimize any confusion. It is also good to start early so that your baby will be exposed to the different languages (able to let him/her get used to listening to the sounds of the different languages). Here is a great link with some tips to facilitate your baby’s learning: http://www.parents.com/toddlers-preschoolers/development/language/teaching-second-language/