Well, it isn't just a matter of software, but hardware. Only newer card readers support SDHC, older ones don't. For instance (I haven't yet bought my Shadow and SDHC card, but I will), I don;t think the built-in SD card slot on my laptop (2½ years old model) will support SDHC. I think I will have to get one of the new USB SDHC card readers (some of the cards come with one) to read and write to the cards from my laptop.
You sure right about that hardware thing, mmmaiki. I tried the patches but Windows didn't accept them because my XP SP3 is newer than the patch. So.... I removed SP3 mainly because I never saw where it fixed any thing for me anyhow. Now the patches applied ok but I could still not read the SDHC. After much more digging, I finally came to realize that my reader is not HC compatable!!! It was sooooo simply. I am now waiting for the Kingston FCR-HS219/1 I ordered from Amazon. $21+ including s&h.
Hope that helps someone else too.