I learned that spoilers can be used on some aircraft for roll control instead of ailerons or in conjunction with ailerons.  When ailerons are used to roll an airplane, they created more lift on one wing and less on the other, rolling the airplane.  With lift comes induced drag so the wing creating more lift also creates more drag so the nose is pulled in one direction or the other.  This is called adverse yaw and it is the reason rudder input is required while rolling an airplane. 

However, spoilers break up or "spoil" the airflow over the top of the wing which so that wing is then creating less lift and drag than the other wing so the airplane is rolled without pulling the nose in the opposite direction.  When spoilers are used the nose is pulled in the same direction that the airplane is rolling which is called adverse yaw. 

I think this is correct.  I am mostly sure about the spoiler thing but I have never flown an airplane with spoilers so I cannot be completely sure.

The spoilers do react in conjunction with the ailerons during extreme bank inputs by the flight controls.  For example, if the pilot turns the yoke fully to the right for a right bank, the right aileron goes up as well as a section of the right spoilers.  They do not go up on both wings.  It only happens on the inside wing (wing on the inside of the turn).  It doesn't necessarily only occur when maximum bank input is given...there is a certain degree of control movement where, when passed, this occurs.  Often in bumpy approaches, as the pilot makes abrupt corections, you might see spoilers move in conjuntion with the airleron because at lower airspeeds, flight controls are less effective and somewhat "mushy" so another control surface (the spoilers) helps give the wing that added push downward to initiate a bank.  

Try flying a 737 in FS.  Move the controls from side to side.  You will see this in action.