A selection of cycling related literature to get you started. If you find a good site that we ought to link to please let me know.
CTC: "More Bikes: Policy into Best Practice" - a CTC report published in 1995.
National Cycling Forum: Advice for cyclists on Cycling Policy (PDF document).
Department for Transport : Local Transport Note 2/08 Oct 2008: Cycle Infrastructure Design - up-to-date planning advice
"Cycle Friendly Infrastructure: Guidelines for Planning and Design" - a significant planning document published in 1996.