ChemGlobe: Iridium: Electronic, thermal, and steric data along with an isotope table.
ChemicalElements.com: Iridium: Basic information, atomic structure, and table of isotopes.
EnvironmentalChemistry.com: Iridium: Atomic structure, chemical and physical properties, and table of nuclides.
Iridium: Data tables and historic information.
It's Elemental: Iridium: Basic physical and historical information.
LANL: Iridium: History, properties, uses, and sources.
Lenntech: Iridium: Physical data, chemical properties, health and environmental effects.
Radiochemistry of Iridium: Full text of the monograph by G. W. Leddicotte (Oak Ridge National Laboratory, Oak Ridge, Tennessee). [PDF]
Visual Elements: Iridium: Image, general and physical information, source, uses, key isotopes, and ionisation energies.
WebElements: Iridium: Extensive information on history, uses, occurrence, compounds, and properties.
Wikipedia: Iridium: Properties of the element, including its history, applications, and characteristics.