Many cities run free and personal tours. These are usually run by volunteer friends, and not professional tour guides but are local people who are happy to show visitors the usual and unusual aspects of their city. A selection of these tours are as follows:
New York City: www.bigapplegreeter.org www.centralparknyc.org
Chicago: www.chicagogreeter.com
San Francisco: www.sfcityguides.org
Australia: Melbourne: http://www.worldtourism.com.au
Adelaide: http://www.bugaustralia.com/
Japan: http://www.jnto.go.jp
Korea: http://english.tour2korea.com
Jamaica: http://www.visitjamaica.com
Bahamas: www.bahamas.co.uk