I am amending the 2010 return because my daughter claimed herself as a non-dependant of me. So it looks like a simple (but expectingly expensive) correction. I believe the correct thinng to do is fill out the 1040X and include a copy of my 2010 return. Because I have it on the computer is it okay just to reprint the return in its entirty w/o signiture (marked as 'Record Copy' or do I need to find a copy of the signed return?
You are correct - that the form 1040X should be used.
You do not need to include a copy of your original tax return because the IRS already has that information.
Do not send anything unnecessary to avoid confusions.
You need only attach forms and schedules that are new or corrected.
On the form 104X - be sure to mark that it is an amended return for 2010 - check the box in the header.
For changing exemptions - fill line 4.
Add Explanation of changes in Part III on page 2.
Do not forget to sign.