How to Change Serpentine Belt
 

This is one of the most simplest task you can do at home and it will about 30 minutes or less.  Serpentine belt is very important.  It power the alternator, mechanical fan, A/C compressor and Power steering.  I have an incident that my serpentine belt broke and I lost all power.  Alternator was dead, power steering wasn't working and so on.  I recommend you should chance this belt once every 50-60k miles.  There are many aftermarket serpentine belt u can get.  One of my all time favorite would be the original Lexus serpentine belt.  The cost is slightly higher, but will worth the money.  The second trust worthy brand would be Gates.  Gates make great quality belts for competitive price.  Here are some aftermarket serpentine belt suppliers. 
Gates part number is K060882
ACDELCO part number is CK882
Kragen Brand 6PK22250

The pictures below are very self explanatory.  I tried to give u details explanation.  Right before you take out the belt.  Its belt to use your left on the socket to release the tensor and use your right hand to remove the belt.  I also included a serpentine diagram.  Good luck.