There's a great "unplugged" session every Wednesday at the Stubbing Wharf Inn in Hebden Bridge, next to the Rochdale Canal (between locks 10 and 11), with moorings right outside the pub. It's not just folk of course but I've sung folk (unaccompanied) there that went down OK. (see http://www.myspace.com/openmicsurgeryorg )

On the first Saturday of the month there's a session at the Anchor Inn, Salterforth, near Barnoldswick (Lancashire, but a lot of Tykes dispute this!) right next to bridge 151 on the Leeds and Liverpool Canal.