There has been a lot of genealogical information printed for the Isle of Lewis. Bill Lawson, who has a genealogy research centre at Seallam, Northton, in Harris has collected a lot. There are printed croft histories which list the lines of descent for croft tenancies. I think a lot of cemetery transcriptions have also been done. You probably need to start with some idea of the village your family might have come from. One of the big problems with researching on Lewis is that there are some incredibly common surnames. Just look in the phone book to see how many pages of names beginning with Mac there are! Also there are a lot of very common first names. I hate to think how many Kenny Macdonalds or Calum Macleods there are! People often became known by a nickname as well.
Local historical societies also collect a heap of information from their area in the way of croft histories. Again, to take advantage of this you really need to know which village your people came from.
I don't have an exact address or website for Bill Lawson, but if you could find him (or Seallam) on the web and contact them direct you may be able to get a list of available publications. Just addressing to "Seallam, Northton, Harris, HS3" may be enough to get a letter there.
