The Skye Trail is a 128km unoffical route running from the North to the South of Skye. It usually takes 7 days to complete and is a fairly difficult route so a good fitness level, experience of hill walking and navigation skills are needed. Camping will make it easier to split the route in to manageable sections, but it is possible to complete the route staying in accomodation as each state is designed to finish either at a town or road.
Further information on the walk can be found at: http://www.skyetrail.org.uk/ and http://www.walkhighlands.co.uk/skye/skye-trail.shtml. The Walk Highlands webpage has the recommended stages and also GPX files if you have a GPS device and I found these very useful. We also used the Harvey Skye trail map and needed no other maps for the route. Cicerone produce a guide http://www.cicerone.co.uk/product/detail.cfm/book/736/title/the-skye-trail#.Va0V7EXjevU which I would recommend for additional information and background to the walk.