I haven't installed any tint myself in years. The real key to a DIY job is to get the glass CLEAN before attempting it. ANY small particle will mess the finished job up.
Don't skimp on the tint...buy a name brand(and no...walmart is NOT a brand name...lol!)
If you plan on doing the rear hatch glass....good luck. The curvature makes it next to impossible to tint with film. Even the pros usually use several pieces on that glass. One large sheet will never lay out right.
I think the hatch glass on my '85 has 3 pieces.
If done right, and a quality tint is used, it lasts quite a long time. Cheaper tint will scratch easily, and usually will peel up at the edges.
I don't mess with it anymore...I would rather pay a pro shop to do it. Takes them about 30 minutes, and is well worth the $$$, imo.
The first car I paid to have done years ago was a Fleetwood Caddy. Took the guy about 10 minutes to do the whole thing, and it was a top notch job.

I had a shop here in San Jose  do it  on my  1988 C4 they used  1 piece and did a  great job  , They did  ruin my  defroster wire  .

I had 3 windows done in "limo"...it turned out just fine and after 2 years of Arizona desert it looks like day one. Would I do it again, I sure would; especially with a graphite interior. The only down side to it is it's quite dark at night. I use my backup cam quite a bit at night.

Had my 90 done with both sides and rear hatch. Paid to have it done, the rear hatch is really hard to get right and well worth paying just for that one alone. I definately would not recommend doing the rear yourself unless you really know what your doing. Once done I think you will love it, I went with 35% which is better for day and night driving (and the darkest legal tint allowed in Tennessee.) But it looks good and really helps with interior cooling and protecting from sun damage.

That's what I'm looking for !    Thanks, guess I'll set some aside and get it done.

|UPDATED|9/30/2012 3:55:17 PM (AZT)|/UPDATED|

I got lucky and saw a special for $150 at Midway Chevrolet in Phoenix.  They recommended a medium density, legal, but the new tints (with either metalic or ceramic in the plastic) are good at reflecting heat and UV.  They said a medium on the hatch and legal tint on the sides would reflect more heat from our Arizona sun than the darker stuff (aka "limo" tint), so I took their advice and it is a God-send.  I leave it in the sun all day at work and it works, plus I can see out the rear view mirror, which I wouldn't be able to do with a limo tint. 

watch the supposedly cut to the exact kits you find on ebay. they rot. when i was putting the 90 back together after the accident i wanted the hatch glass tinted darker and did it myself. there is a trick and i think it came out great.

i went into autozone and they have a few different types of tinting. the one that caught my eye was the one that is like the static cling things you stick on windows.

i had the window off the car which makes it much easier to work. the trick to doing this kind of window is pretty easy. as was stated as the curve of the window it is best to cut it in strips. the manufacturer suggested 6" but i made mine a little wider.

here is the way i did it. i cut the strips to the width i needed. with the window on a flat surface the outside facing me i positioned each strip and cut it to fit in place. you must remember to keep the side that goes to the window facing up so you are actually cutting it like it was on the inside of window. i did this with each strip.

take the strips and lay them to the side and flip the window over. now you can apply the strips as per the instructions as they are precut and should fit perfectly. mine came out great and is still looking great. what i like about the tint i got is that you can remove it and then reapply it.