The stamps come out today and you can get cancellations from Colorado:
SIMPSONS POSTMARK, POSTMASTER, 188 E 9th AVE, SPRINGFIELD, CO 81073-9998
To get the cancellation, one should be able to send Stamped, Self-Addressed Envelopes within 30 days to:
The Simpsons Station, Springfield, VT 05156
If anyone hears of anymore, please let me know.