Your thoughts/tips/advice on focus stacking? Best intro web reference to focus stacking?

I have a Nikon D5100 and when I take close-ups I often wish more of the subject to be in focus.

I have heard of "focus stacking" -- is it complex or difficult?

Can it be done in camera?

If software is needed, is there any free, or free trial software I can use to try out focus stacking?

If the subject is moving, is there a way to combine subject tracking and focus stacking?

Can you look at a finished photo and tell whether it is the result of "focus stacking"?

~ thanks for your answers ~

There are several tutorials online. Google is your friend.

Yes, is complex and diffcoult and it can't done on camera… But is not impossible ;-)

software free: http://www.hadleyweb.pwp.blueyonder.co.uk/CZP/News.htm

software trial: http://www.heliconsoft.com/heliconfocus.html or http://zerenesystems.com/stacker/

for any question: http://www.photomacrography.net/forum/