Curtis brings up some good points --- but not completely accurate, or even proper under the law... There's really no law that states you must render aid. And I, for one, would not. Doing so may in fact bring about a whole new set of circumstances such as "destroying evidence" or doing more harm than good etc. Another factor you should consider is that there very well maybe another intruder you're unaware of "yet"... and now you're disarmed and distracted.
Best to just call 9-1-1 and let them sort it out.
BTW - The last thing I want to do is to shoot someone -- and then have them survive and sue me for taking care of them for the rest of their lives on a ventilator. No thanks!
EVERYONE should understand the laws IN THEIR STATE... as pertains to defending ones property and person.
The laws vary greatly! Part of your responsibility of owning firearms is that you should know the laws. Many states laws are vague at best. But in the end - if you did the
reasonable and right thing in the circumstance... you're probably going to be okay.
http://en.wikipedia.org/wiki/Stand-your-ground_law