Zirconium

ChemGlobe: Zirconium
Electronic, thermal, and steric data along with an isotope table.
http://partisans.spurious.biz/~pkremer/projects/chemglobe/ptoe/_/40.html

ChemicalElements.com: Zirconium
Basic information, atomic structure, and isotopes.
http://www.chemicalelements.com/elements/zr.html

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

It's Elemental: Zirconium
Basic physical and historical information.
http://education.jlab.org/itselemental/ele040.html

LANL: Zirconium
History, isotopes, properties, and uses.
http://periodic.lanl.gov/elements/40.html

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

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

Visual Elements: Zirconium
Image, uses, physical information, and ionisation energies.
http://www.chemsoc.org/viselements/pages/zirconium.html

WebElements: Zirconium
Extensive information on history, uses, occurrence, compounds, and properties of the element.
http://www.webelements.com/webelements/elements/text/Zr/key.html

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