1 : Use a custom forked version of the original arduino IDE to get these little bad boys up running quickly.
2: The original IDE but it is much more involved.
I went the easy route
These Attiny85 clones are actually pretty amazing little boards and super cheap. You are very limited to what you can and cannot do. A good majority of the libraries for the original arduino will not work with these Attiny85's. Because of all these limitations in place it will make you think outside of the box. Remember you only have 6 pins to work with. A plus is you can run software serial on 2 pins which is a good and it will work with I2C.But like i said keep an eye on the pin count. 6 is not a lot.
I will be using these to shrink down my Uniden U Control even more. I should be able to fit everything inside the small Altoids tin. The WIKI link below will have all the information you will need to know...
My cell phone was jammed under my neck so i could get my hands free :)