Mercury News reports that based on their investigation, there is little evidence to support criminal charges against Steve Jobs for the stock-option backdating investigation that first made headlines in June 2006.
Despite Apple's disclosure that Jobs approved widespread backdating at Apple, there is no evidence he directed the backdating of his own grant or covered it up afterward, based on a review of regulatory filings and interviews with lawyers intimately familiar with the grant who asked not to be identified.
Mercury News provides an excellent summary of the history of the backdating irregularities at Apple. The main issue surrounds an initial meeting on August 29, 2001 where the board had discussed granting Steve Jobs 7.5 million shares, but negotiations continued, delaying the finalization of the stock options. The grant was finalized in December, but the options were backdated to October 2001 with falsified meeting minutes related to the options grant.
The article points out that backdating, itself, is not necessarily illegal, though who was responsible for the falsification of documents remains a point of contention.