The website for the marathon you are running should have all the information you need about registration. You can usually register online, by mail, or in person before or the day of the race.
To give you and idea - registration opened September 9th for the 2010 marathon. see: http://running.competitor.com/2009/09/news/2010-boston-marathon-registration-open_5297
Registration should be open around the 2nd week of February
Not yet. The Boston Marathon typically opens registration on the first Wednesday of September.
Sunday, October 11, 2010 http://www.runtri.com/2009/01/Chicago-marathon-2009-registration-and.html
It sold out on March 24 for the 2010 Chicago Marathon. Registration opened on 2-1-2011 for this year.
Registration for the Bank of America Chicago Marathon began on February 1st. See the related article.
Registration for the ballot starts on 30 April
Registration for the 2012 Boston Marathon begins on September 12, 2011 and ends on September 23,2011. Registration dates also depend on qualifying times and these vary based on age,gender,and physical impairments as well.
The winner of the 2012 Chicago Marathon, Kebede from Ethiopia, won $100,000 plus $50,000 for setting a new record.
Sunday, October 11, 2010 http://www.runtri.com/2009/01/chicago-marathon-2009-registration-and.html
You should register for the Bank of America Chicago Marathon as early as possible. This year, registration began on February 1st and last year it closed in late March.
Researching to find a Marathon Turkish website has not provided any results matching this name but there is a site that is called Istanbul Marathon. This site offers registration and marathon information for a number of marathons that are sponsored such as the 8 kilometer fun run.