How did Americans treat the few Japanese soldiers who surrendered in the Pacific Theater?

As you say, there were exceedingly few Japanese taken as
prisoners of war by the United States.  Some sources say that as few as 5,000 were taken
by the US and brought to actual camps in the United
States.

Of course, some Japanese were not allowed to
surrender by US troops.  It is not surprising that soldiers in the heat of battle would
kill some enemy who were attempting to surrender.  So I will not claim that all Japanese
attempting to surrender were treated well at all times.  However, the general situation
is that Japanese POWs were treated well.

One reason for
this is that good treatment of the POWs is said to have yielded a good deal of
intelligence.  Japanese soldiers were trained to expect terrible treatment at the hands
of the enemy and tended to react well to kind treatment.  In addition, they were not
well trained in trying to resist interrogation because they were not supposed to be
captured.  The Americans treated them well and got intelligence in
return.

For those few who made it to prison camps on the US
mainland, treatment was good.  The Japanese, unlike European POWs, were not made/allowed
to work outside the camps for fear that they would be targeted by angry Americans for
violence.  However, the conditions that they experienced inside the camps were, like
those experienced by German and Italian POWs in the US, quite
good.

For more on this subject, see if you can find href="http://www.amazon.com/exec/obidos/ASIN/0295983361">this
book.