Thomson Reuters has just released the 2009 Journal Citation Reports (JCR). From the press release:
"The most widely used tool for assessing the world’s leading journals, JCR and the metrics it offers — including Journal Impact Factor — empower users to objectively evaluate a journal’s performance and its influence on research globally. "
The U of S Library subscribes to JCR - so you can check out the Impact Factor of your favourite journal by finding Journal Citation Reports under the "J" in our Databases list. Or you can click on this link.