here is a good line:
"No Power of Attorney survives the death of the principal. The authority to use a Power of Attorney ends with the death of the person giving the authority. A Power of Attorney may be revoked at any time by the principal. Such a revocation must be in writing, and if the original Power of Attorney was recorded at the Courthouse, the revocation must also be recorded."
from this site:
http://www.secured-title.com/new_page_9.htm Well that seems pretty clear-cut. All the Google-ing I did and I didn't turn up anything that definitive.
Thanks for taking the time!