Primitive Christianity Revived, Again
A Short History of Conservative Friends is a wonderful introduction to the origins of the Conservative Friends movement. It includes the 1912 Conservative Statement of Faith, which is about as close to an official definition that exists.
What do Conservative Friends Believe? from Michigan's Crossroads Friends Meeting is a useful contemporary description of one meeting's understanding of Conservative Quakerism.
Friends of Jesus is a group organizing a fresh mix of Conservative Quakerism and an outward-reaching progressive evangelical Christianity.
Wikipedia has a relatively good article on Conservative Friends.
Ohio Yearly Meeting, Iowa Yearly Meeting Conservative and North Carolina Yearly Meeting Conservative are the three official Conservative yearly meetings. NCYMC publishes an occasional Journal available by PDF.
New Foundation Fellowship US and New Foundation Fellowship UK have traditional Quaker leanings and act as support networks for isolated Conservative Friends and seekers.