Lithium

ChemGlobe: Lithium
Electronic, thermal, and steric data along with basic information.
http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/3.html

ChemicalElements.com: Lithium
Basic information, atomic structure, and table of isotopes.
http://www.chemicalelements.com/elements/li.html

Corrosionsource.com: Lithium
History, properties, sources, and uses.
http://www.corrosionsource.com/handbook/periodic/3.htm

EnvironmentalChemistry.com: Lithium
Atomic structure, chemical and physical properties, and table of nuclides.
http://environmentalchemistry.com/yogi/periodic/Li.html

It's Elemental: Lithium
Basic physical and historical information.
http://education.jlab.org/itselemental/ele003.html

LANL: Lithium
History, sources, uses, and cost.
http://periodic.lanl.gov/elements/3.html

Lenntech: Lithium
Physical data, chemical properties, health and environmental effects.
http://www.lenntech.com/Periodic-chart-elements/Li-en.htm

USGS Minerals Information: Lithium
Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).
http://minerals.usgs.gov/minerals/pubs/commodity/lithium/

Visual Elements: Lithium
Image, general and physical information, and key isotopes.
http://www.chemsoc.org/viselements/pages/lithium.html

WebElements: Lithium
Extensive information on history, uses, occurrence, compounds, and properties of the element.
http://www.webelements.com/lithium/

Wikipedia: Lithium
Properties of the element, including its history, applications, and characteristics.
http://en.wikipedia.org/wiki/Lithium