Please note that I am not an engineering consultant. I write and lecture on the subject of wind energy and increasingly on other sources of renewable energy as well. I do provide advice to governmental, non-governmental, and advocacy organizations. I can provide referrals to technical consultants upon request, some that I recommend are listed below. Note also that as a free-lance writer I do not sign non-disclosure agreements. While I respect confidentiality, I am under no obligation to do so.
There are dozens of firms worldwide providing professional services to the wind energy industry. There also a number of planning bureaus in Germany that specialize in siting medium-size wind turbines throughout Europe.
AeroVironment Inc
www.aerovironment.com
BTM Consult
www.btm.dk
Garrad Hassan
www.garradhassan.com
Wind Utility Consulting
tomwind@netins.net
For an interesting and well written commentary on what it's like to own a 1.8 MW wind turbine visit Glen Estill's blog.
Wind Risk also operates a news group on questions of operations and maintenance of large wind turbines at their blog.
The following are meterological consultants that I have worked with or who have helped me to understand wind resource assessment. They are professionals and because of the boom & bust nature of the wind market in North American can be extremely busy. They can't take the time to answer general inquiries. They do provide wind resource assessments that will withstand the scrutiny of a banker. Wind studies cost from $25,000 USD to $40,000 USD or $25,000 CAD to $50,000 CAD, depending upon the amount of work required.
Nierenberg & Assoc.
ron1230@comcast.net
Resource Assessment & Micrositing
windmet@pacbell.net
Zephyr North
www.zephyrnorth.com
Remember that trade associations are in business to promote their member's products. You won't find information about the German manufacturer Enercon on the web site of the Danish Wind Turbine Manufacturers Association. Many of the European web sites are offered in English as well as the host language. Some, such as Vindmølleindustrien's extensive web site, are presented in English, German, French, Spanish, and Danish.
RenewableUK (BWEA)
www.renewable-uk.com
Bundesverband Windenergie (German Wind Turbine Owners Association)
www.wind-energie.de
Fördergesellschaft Windenergie (Geman Wind Turbine Manufacturer's Association)
www.wind-fgw.de
Canadian Wind Energy Association (CanWEA)
www.canwea.ca
New Zealand Wind Energy Association (NZWEA)
www.windenergy.org.nz 
Vindmølleindustrien (Danish Wind Turbine Manufacturers Assoc.)
www.windpower.org
World Wind Energy Association
www.wwindea.org
One of the best site in Français is that sponsored by the University of Quebec at Rimouski, www.eolien.org
The web site for the French wind energy association is France Energie Eolienne
fee.asso.fr
There are a number of excellent www sites in German. These are often presented in English as well. Some sites use machine translation which leaves a lot to be desired.
There are two organizations in North America that are actively encouraging community-owned or farmer-owned wind development: Windustry in Minnesota, and the Ontario Sustainable Energy Association in Canada.
There are also a number of organizations and environmental groups that support wind energy. One web site that tries to debunk many of the myths surrounding wind power is Greenpeace's Yes2Wind.
Windustry
www.windustry.org
Ontario Sustainable Energy Association
www.ontario-sea.org
Yes2Wind
www.yes2wind.com
Pro Wind Alliance
yesPro Wind Alliance--A voice of reason in the British Isles not connected to any trade association. 
World Future Council
World Future Council supports the use of Advanced Renewable Tariffs (feed-in tariffs) to encourage the rapid development of renewable energy. Community ownership of renewables is only possible where effective feed-in tariffs are in use.
For testing of small wind turbines and for all around helpfulness on the subject of wind energy no one beats the Alternative Energy Institute at West Texas A&M University. The Folkecenter for Renewable Energy is a long-standing reference source on the success of Electricity Feed Laws and Community Wind development in Europe. The Midwestern Renewable Energy Association has long been an ardent proponent of renewables, not just wind energy.
Alternative Energy Institute
www.windenergy.org
Nordvestjysk Folkecenter for Vedvarende Energi (Folkecenter for Renewable Energy)
www.folkecenter.net/gb
Midwest Renewable Energy Association
www.the-mrea.org/
For an insightful account of the history of the Danish wind turbine industry and the role they played in the development of modern wind energy see Erik Grove-Nielsen's web site at Winds of Change. The site contains one of the best collections of photographs from the period as well as a hard-to-find collection of historical photographs.
For tips on the design of small wind turbines visit the sites of Scoraig Wind Electric's Hugh Piggott, www.scoraigwind.co.uk, and Windmission's Claus Nybroe, www.windmission.dk.
If you need parts, service, or advice on how to maintain your small wind turbine, you can subscribe to the yahoogroup small-wind-home. There are several knowledgeable participants on this list who offer a wealth of technical information. Once you've subscribed, monitor the list, then, when you're ready, post your question.
There is also a discussion group on small wind turbines (petit eoliens) in French at http://fr.groups.yahoo.com/group/petit-eolien/.
