I think you first have to define what you mean by Ley Lines. A recent article I read suggested that the original hypothesis for them ( 1920s?) was that the ancient monuments scattered around the UK could all be connected by straight lines, and this was somehow tied in with navigational aids.
It was only later ( late 60s?) that the new age "spiritual energy" dimension became attached. This spiritual energy is something I am highly sceptical of, just as I am of dowsing, come to that.
Some interesting references for you .... first, a nice little website you can use to determine how spiritual your own address is....
http://www.tomscott.com/ley/
Then, a sceptical view of ley lines. You pays your money, you takes your choice.... I think its all pretty much cobblers myself ;)
http://www.skeptical-...l-ley-lines-debunked/
(this is the article I was thinking of when i first started this post)
http://blogs.discover...debunking-down-under/
(link to a dowsing video and read the post in the comments re dowsing at Avebury)