If you want your xbox controller to function correctly for games that have native support for controllers...
Just plug it in.
If you want your ps3 controller to function correctly for games that have native support for controllers...
DS3 Tool
If you want your xbox controller to be used for games that do NOT have native support for controllers...
Use joy2key or xpadder.
For PS3 controllers for games that do NOT support controllers...
DS3 Tool, joy2key and xpadder are optional.