This a growing collection of projects that feature the awesome ATtiny IC.

diy_bloke is Instructables 433MHz expert.
I like that this does not use an Arduino as transmitter. Make sure you check out updated info in the comments.
Well done tutorial (Ible) on the ATtiny. I love these little low cost MCUs.
Look at this! I'm really impressed with what's being done with these little guys.
Program your ATTiny IC
Up to date tutorial
Going to try this because some the other "Program ATtiny with Arduino" seem a little old, although they did work.
This a fantastic bit of work. i love it.
Even though I don't program an ATtiny every day, making and using a programming shield is just fun. And to me that's what hobby electronics is all about.