Arduino-tiny Attiny45 PWM pins not working properly?
The ATTiny25/45/85 have three PWM pins, but AFAIK the HLT group's Arduino core only exposes two.  There's an entire thread on this subject over on the Arduino forums: http://forums.adafruit.com/viewtopic.php?f=24&amp;t=23937

The datasheet is your go-to reference for these issues.  There's a lot of misinformation posted on vendor sites.  Learning how to read the datasheets for these devices is an extremely valuable skill.  The datasheet is here: http://www.atmel.com/images/atmel-2586-avr-8-bit-microcontroller-attiny25-attiny45-attiny85_datasheet.pdf

Note: there is also a bug in earlier revisions of the ATTiny45 (prior to Rev. D) that prevents PWM from working properly on pins 3 and 6 (OC1B, OC0B) if PWM is not also enabled on pin 5 (OC0A).