flash MX tab between text fields

First put this in the _root in the timeline. change 'mc' to the name of your mc that you are wanting to tab in.

mc.tabChildren=true;

Now inside of your mc, put this in the timeline. Be sure to change 'txt1' and 'txt2' to the instance name of your text fields you wish to tab between:
txt1.tabIndex = 1;
txt2.tabIndex = 2;

To tab between buttons put this but change 'btn' to the name of your button.:
btn.tabIndex = 3;