Steve Hunts has questions about DIY tinting.  I've used material from JCWhitney
which offers several different percentages of tint and at least two colors -
grey and bronze.  You can get the same stuff at a big FLAPS.  Prep requires
glass cleaner, razor blade, glass cleaner, razor blade, glass cleaner.  Use
lintfree fabric, not newsprint or paper towel, for the last two cleanings.  Do
the rubber seal around the glass real well, or dirt will wash off it just when
you don't want it.  I cut the material about 2 in oversize in each dimension
and trim it on the window with a real sharp blade.  Follow the directions
faithfully but still do someone else's van first if you can.  On American vans
where the windows are bolted rather than sealed in, take the windows off and
do them on a horizontal surface; it's much easier.  

The place to do it is as brightly lit as a sunny day, but as windless as a
livingroom.  A large clean table next to the van helps.  Don't hurry.   Two
extra hands are helpful if they like you but one person can do a good job
too.

Post here if you buy the material and don't understand the concept after you
read the directions.  I'm sure I'm not the only one who's BTDT.
B.