Get ready for massively larger SD cards.

Today, the SD Association announced a new SD card specification: the SDXC. The XC stands for eXtended Capacity. SDXC cards promise capacities as large as 2 terabytes, as well as a faster bus speed.

According to the SD Association, SDXC cards are expected to reach “read/write speeds to 104 megabytes per second this year, with a road map to 300 megabytes per second.” They will have the same physical dimensions as the current generation of SD and SDHC cards.

Tapping into SDXC’s higher capacities and faster speeds, digital cameras would be able to save full-resolution images continuously onto the card (no longer be limited by the size of the memory buffer). Flash-based camcorders could save continuous ultra-high-speed video, similar to the video generated by the Casio EX-FH20, directly to the card. And handheld audio recorders could potentially store 5.1 or 7.1 surround sound to a card in real time.

Look for SDXC cards to possibly trickle in by the end of the year, with a full launch set for 2010.

As you might expect, your devices would need to be compatible with this new format. That means you’ll have to buy a whole new round of gadgets to take advantage of these new capabilities. SDXC is backwardly compatible, so your current SD and SDHC cards should work in your new SDXC-compatible devices.