Will the US postal service be issuing a special commemorative postmark
in celebration of the centennial of the 1906 earthquake and fire in
San Francisco?  If so, where should I send my special covers in order
to get them cancelled with the special postmark?

Dear Zozzle, 

"The San Francisco District of the United States Post Office is
offering a limited edition commemorative cachet celebrating the 100th
anniversary of the earthquake. See 'Stipulations' for more details...
Stipulations

"OWN A PIECE OF HISTORY..." Send $5, check or money order to
EARTHQUAKE CENTENNIAL, PO BOX 880188, SAN FRANCISCO CA 94188-0188.
Ensure your name & return address are legible. Cachet has special
postmark and a picture of the San Francisco Main Post Office (7th &
Mission Street) taken after the great quake. ORDERS WILL BE FILLED
AFTER APRIL 18TH, 2006. Hurry while supply lasts...
Nature of Offer / Solicitation

Other
Contact: peter.h.deutsch@usps.gov" 
(SOURCE: 1906 Earthquake Centennial Alliance, Clearinghouse,
<http://1906centennial.org/clearinghouse/>).

I hope this answers your question. Please contact me if you need any
clarification on this answer before you rate it. My search terms:
[1906 	earthquake 	commemorative 	postmark ]