Here is a collection of links that no Iridium or Flare lover should do without: 

First of course the one and only …
Iridium Communications

… and their section dedicated to the end of a legendary era
#flarewell

The repository of the most beautiful Iridium Flare pictures with only two satellites missing:
Catch The Iridium

Celestrak has separate sites with TLE of both constellations as well as a fascinating visualization tool:
Block 1 Satellite TLEs  and visualization
Iridium NEXT Satellites and visualization

CalSky is one of the very few sources that predicts tumbling Iridium (and a handful of others) satellites for your specific location
CalSky

Rod Sladen has been following the orbital maneuvers of Iridium satellites for what seems to be decades and keeps tabs on all the changes
Iridium Constellation Status

Stuff In Space is a great visualization tool that shows you where the Iridium satellites (and just about all the others as well) are currently orbiting
Stuff In Space

SatFlare is a site that shows satellite passes and flares (sigh!) but is also a good resource for reentry predictions
SatFlare

Iridium Where is another fansite that covers the status of the constellation and offers a live map of the current location of all Iridium satellites in orbit.
IridiumWhere