Esp8266 timers

I am starting to use Esp8266 with Arduino core and I am interested in porting some sketches to the esp8266 that use timers on AVRs. I have read through the core files and internet documentation but I am looking for a clear explanation on how esp timers can be used. I have seen references to Timer0, Timer1, Timer2, os_timer, hw_timer, FRC1, FRC2. My questions are:

  1. What are the available esp timers, how do they work, what do they normally do?
  2. Which timers can be used like the AVR timers, without interfering with anything?

Thank you.

A bit old and may be out of date now but have a look here

Another alternative might be the Ticker library that is part of the esp8266 download.