Useful strategy resources online

General websites directly relevant to strategy

Strategic Management Society: www.smsweb.org 
Strategy Club: www.strategyclub.com 
Academy of Management: www.aom.pace.edu 
Boston Consulting Group: www.bcg.com 
Michael Porter's Institute for Strategy and Competitiveness at Harvard Business School: www.isc.hbs.edu/index.html

Often there are websites associated with new areas relevant to strategy. For example the area of real options which is highly relevant to strategy has a growing number of related websites. 

For example there is a website associated with the popular book by Amram and Kulatilaka (Real Options: managing strategic investment in an uncertain world, Harvard Business School Press, Boston, Mass.: 1999): www.real-options.com

Sometimes there are websites associated with annual conferences dealing with the topic:
www.realoptions.org or a group which specialises in research in the relevant area: www.rogroup.com

At other times the website is the result of an individual's interest. For example:
http://homepage.mac.com/j.norstad or: www.valuesweep.com/additional_realoptions.html

It is valuable to do a search on such concepts as the balanced scorecard approach or blue ocean strategy, to pick just two new ideas.