ultimatemegax, a known fan-translator who translated the bonus novel that came with The Surprise of Haruhi Suzumiya had just finished translating both volumes of the main novels. The Surprise of Haruhi Suzumiya came as two volumes, volume 10 and 11 starting from chapters 4 to 9 (read The Dissociation of Haruhi Suzuimya (9th volume) for chapters 1-3). The story continues from the cliffhanger in The Dissociation of Haruhi Suzumiya. So check the link to his blog below for the translations! (including the bonus novel).
(if the link is taken down from his site, ask me for the novels in PDF format).