I bought a Toshiba laptop last summer (2007) that has an SD slot, but won't read SDHC. I've got an SDHC card in my camera. Maybe I'll try it when I get home.
It should be compatible with SDHC (and micro-SDHC) memory cards. Most SD memory card devices made during and after 2005 are SDHC compatible. I have a Creative Zen that was made in 2006 yet it is SDHC compatible with cards up to 32GB in size. I don't have any SDHC cards to test though. You could always put content on your SDHC card, take it to a store like GameStop, and ask them to try it out on their demo unit. I conducted a Google search (took an amazing 3 seconds, Google is your friend) for SDHC PS3. There is a thread on the unofficial PS3 forums where someone stated their 8GB SDHC card worked with their PS3. They said that their card was Class 2 which are the slower cards but still much, much faster than standard SD.
You could always go out and purchase a $20 memory card reader if the PS3 isn't compatible with SDHC memory cards.