Pentax Japan released the firmware update 1.01 for Pentax Optio A20 and Optio S7 digital point & shoot cameras.
Both updates adding SDHC memory cards compatibility. E.g. now you can use SD cards larger than 2Gb with this cameras.
Download update for S7 here and for A20 here.
"How to install" instructions could be found on the pages linked above.