Other
Web ref.org: Iridium
A student friendly site with basic information (and links to definitions or examples of key terms) on iridium. Good job on uses.
Chemicool
Chemicool: Iridium
This site from Chemicool and David D. Hsu is a well organized set of tables summarazing all sorts of helpful information on iridium. A good place to find data on physical properties.