Sdhc To Sd What Is The Difference Between An SDHC Card And SD Card For Digital Cameras? ?

What is the difference between an SDHC card and SD card for digital cameras? ? - sdhc to sd

I recently ordered my first SLR camera - is not there yet - and I understand that the SDHC card was used. I have regular SD cards that work or do I will buy a new one?