Pixie,

There are a number of guide books to do the ridge way from south to north, which for some is arse about face, but works for me. Ordnance Survey produce a good one, a little longer than A5 size detailling the whole thing, whichever way you want to do it, but this one starts in Avebury, features circular walks & attempts to explain a few things along the way. There is a bit of confusion doing it this way round though as the further up you go, say around Goring, you get paths which are the old ridgeway & new ridgeway. My advice here is simple, go with whatever your gut tells you.

Book available in Smiths or any map shop, it's about a tenner & they do them on the south downs way, offas dyke, etc.

Have fun

Blaidd