A Complete Guide to SD Memory Cards

Most SD cards measure around 32 by 24 by 2.1 mm in dimensions. However the thickness varies and they can be up to 1.4 mm slim. These cards are also asymmetrical in their shape so that one cannot insert the card into the slot upside down. You will also find that the contacts are recessed so they cannot be easily damaged. The data transfer rate is especially high with an SD memory card which makes them preferable to other storage media.

I'd like to get some info on the mini (and micro) SD's too. Also, I have been wondering about the SDHC (high capacity) card. I know my Canon digicam will accept them, but before spending big bucks on one, will my card reader on my PC accept them? Specs on the PC's reader just mention SD.
One thing I've learned researching the SDHC Cards is that there are 3 classes of them, Class 2, Class 4, & Class 6. The class number tells the cards data minimum transfer rate (2 MB/s, 4 MB/s & 6 MB/s).
{Edit 9-01-08} I bought a 16GB SDHC and NO it will not recognize it in my SD card slot. The new SDHC card came with a USB reader so all is well.

Thanks very much for sharing ... It's really is a very informative thread and it's pretty much solve my problem as well.