Got my Kickstart Reward ATtiny85 ISP and made it Blink. (Feb. 2013). Had some difficulty with older tutorials etc on programming the ATtiny85 using my UNO R3(clone) as an ISP. Success via download of 1.5.5 IDE and ATTiny files including cores from here:https://code.google.com/p/arduino-tiny/
Made the /hardware/tiny folder in my Sketchbook and things went OK from there after copying the tiny folder from the link above (version: arduino-tiny-0150-0020.zip). You have to have a boards.txt file as described in readme. Used ATTiny85 internal 8 MHz board option and left heartbeat delay at 20 in the ArduinoISP sketch from 1.5.5.
Some older How To & references to ATTiny programming with an Arduino as ISP had folks reverting from 1.0.x IDE to 1.0.1 or even earlier environments. One ref. said Uno wouldn't work. One had the change in heartbeat that was not necessary any more. Looks like the Uno and 1.5.5 are good to go for ISP programing of the ATTiny85. Worked w raw chip and with the ATtiny85 ISP board. I used the LEDs on pin 7,8 and 9 as per the Arduino ISP sketch directions for additional visual clues.
As noted elsewhere "On the Arduino Uno, you'll need to connect a 10 uF capacitor between reset and ground "
Hold Shift to download using programmer in IDE, as Ben noted. Ordered a ISP shield before I got my Uno working w the most recent IDE and the ATtiny 01500-0020 above. Oh well, will likely be easier to use and give me a nice ISP 6 pin cable...