I've just purchased a 8GB SDHC card for my soon to arrive Canon G9.
Not surprisingly my current card readers don't accept it and no doubt I'll need to upgrade, this I can accept and USB card readers are not "break the bank" items. However owning a Epson P2000 this could be an issue for when I travel as I generally dislike lugging a laptop around with me.
I've seen SD to CF adaptors and doing a quick google search I've been able to find a few SDHC to CF adaptors - I'm guessing/hoping these make the SD card fully readable by devices like the P2000.
Also - for the p2000 - I'm not to worried about the fact that the adaptors I'm seeing are larger (longer) than a standard CF card as they aren't fully enclosed by the reader and don't need a door/gate closed like say my 20D camera. But was interested in knowing if there were any standard size CF adaptors that the SDHC card could sit in that would make them usable in my cameras that use CF. I've seen this done with standard SD and other smaller cards but given that SDHC seems to be "the next big thing" and, at least here, SDHC is quite a bit cheaper than CF memory of the same capacity/speed it might be an option to consider to move some of my storage over time to SDHC+ CF adaptors rather than CF.