If you attended the Mirrodin prerelease tournament this past weekend, then you should have a prerelease card in your possession. If not, here's what you missed out on:
The card is Sword of Kaldra, a rare artifact Equipment. The prerelease version has different art than the version in the set. The Mirrodin expansion symbol is foiled in the text box, and the date (20 Sept 03) is stamped above the type line in gold leaf.