Not common, but extremely useful for those with access to them. Saves a lot of resources. Please add any others you know of, or other unusual library collections (I've heard of toy libraries for instance)
Grosse Pointe Central Library Tool Library
Central Branch~
10 Kercheval Ave at Fisher rd
Grosse Pointe Farms, MI 48236
(313) 343-2074
http://www.gp.lib.mi.us/information/about/toollist.htmlPhinney Neighborhood Association Tool Library
6532 Phinney Ave. N
Seattle WA 98103
(206) 783-2244
http://www.phinneycenter.org/programs/tool-lending.shtmlTool Lending Library
Berkeley Public Library
1901 Russell Street
Berkeley, CA 94703
(510) 981-6101
http://www.berkeleypubliclibrary.org/tool/index.htmlOakland Public Library
Temescal Branch
5205 Telegraph Ave.
(510) 597-5049
http://www.oaklandlibrary.org/Branches/tem.htmSearcy Creek Parkway Neighborhood
Kansas City, MO
http://www.nni.org/scpna/tools.htmCity of Takoma Park, MD Tool Library
http://207.176.67.2/ecd/housing/index.htmlNORTH CENTRAL NEIGHBORHOOD Tool Lending Library
Loma Linda Redevelopment Agency
25541 Barton Rd.
Loma Linda Ca 92354
(909) 799-2810
http://www.ci.loma-linda.ca.us/site/tool_lending_library.htmMobile Tool Library Program
Columbus, OH
http://td.ci.columbus.oh.us/Housing/mobile.tool.htmUniversity of Oregon East Campus Housing Tool Library
http://darkwing.uoregon.edu/~ectools/EC.htmSouth Wedge/Corn Hill Tool Library
Rochester, NY
http://www.cornhill.org/tool_library.htmlMUD Tool Library
Missoula, Montana
http://www.missoula-neighborhoods.org/neighborhoodprojects/neighborhood%20project%20page.htm(scroll down)
San Francisco Public Library
Tool Lending Center
http://sfpl.lib.ca.us/librarylocations/branches/toollending.htmIn Vancouver, an interesting small tool library that is organized as a list of individuals who own and are willing to share particular tools.
http://www.singlemotherssupportnetwork.org/tools.htmlAnd in Australia, a tool library at a university.
http://www.latrobe.edu.au/union/SER/tool_lib/catalogue.html