Free Surname Search - links to a great variety of different indexes which can be searched at no charge. Some provide a different interface to databases, e.g. the IGI, some are indexes for particular localities, e.g. a census index for one place.
The following books are all useful guides to Scottish genealogical research: [Note that other editions of some of these books, for instance in the USA and Canada, have been published]
Discover Your Scottish Ancestry - Internet and Traditional Resources by Graham S Holton & Jack Winch - Edinburgh University Press 2003 I.S.B.N. 0 7846 1864 3.
A rather old publication but still of great value:- Sources for Scottish Genealogy and Family History by D.J.Steel, published 1970 by Phillimore & Co. Ltd. for the Society of Genealogists (National Index of Parish Registers" volume XII).
My ain folk by Graham S. Holton and Jack Winch, published by Tuckwell Press, East Linton (1997, 150 pages) with ISBN 1 86232 024 1. This is subtitled "an easy guide to Scottish family history" and includes information on using the Internet to help with your research.
Tracing your Scottish Ancestry by Kathleen B. Cory, published by Polygon, Edinburgh (1996, 2nd edition) with ISBN 0-7486-6215-4.
In Search of Scottish Ancestry by Gerald Hamilton-Edwards, published by Phillimore, Chichester (1983).
Scottish Roots by Alwyn James, published by the Saltire Society, Edinburgh (1995, 159 pages) with ISBN 0-85411-066-6
Tracing Your Scottish Ancestors (a guide to ancestry research in the Scottish Record Office) by Cecil Sinclair, published by the Scottish Record Office (now renamed the National Records of Scotland), Edinburgh: HMSO,1997 (revised edition). ISBN 0-11-495865-3.
Tracing Scottish Ancestors by Rosemary Bigwood, published by Harper Collins (in Collins Pocket Reference series) in 1999, ISBN 0004723287 (288 pages).
Your Scottish Ancestry: A Guide for North Americans by Sherry Irvine, published by Ancestry in 1997 ISBN 0916489655 (267 pages).
Gathering the Clans - Tracing Scottish Ancestry on the Internet by Alan Stewart, published by Phillimore in 2004, ISBN 1-86077-291-9.
For information on previously published family histories (particularly landed families), see the following publications: