Harrington one behind as Woods and Wilson share half-way lead

American duo Tiger Woods and Mark Wilson shared the lead at the end of the second round of the BMW Championship in Illinois.

Wilson was the long-time clubhouse leader after a second-round 66 vaulted him up the leaderboard and onto seven under, but the 34-year-old saw his advantage gradually eroded by Woods, who secured a share of the lead with a birdie on the 17th.