I got a 2G iPhone with a broken screen.
Luckily the digitizer still working and the serious cracks not really reached the screen itself, apart a small fracture from the clock area.
So, I decided to repair it somehow DIY, because a proper screen-repair could cost you around 120 GBP.

Step 1: Clean Up the Mess

You will need: iPhone 2G keen to survive
tweezers
some used top-up or sim-card
scissors
pen or pencil
sandpaper
clear liquid glue
Some alcohol
Black acrylic paint
a bit of developed 35 mm film negative
good eye for details
iPhone screen protector (optional)

Firstly I removed the broken glass chips from the seriously damaged area with a tweezer. Under those there are the speaker and the light sensors.
I fixed the remaining shivers over the clock area with a model-kit glue,because I want to see the clock.

Step 2: The Right Shape

As I found it out a regular top-up or sim card have exactly the same thickness as the glass. Ideal for fill up that gap. Easy to cut, not too soft nor too hard, you can draw on it and easy and cheap to get.

I used a transparent piece of plastic (or it could be a paper too) to get the guideline to cut the plastic-card for the right shape around the crackline.
Check how it fit after every cut! Use sandpaper to shape the rims of the corners. Then carry on until everything is just fit.

Step 3: Holes

OK, make those holes for the speaker and the light sensors. I used the same transparent card and drilled them together to align the right positions of the holes. Check and check again.
After everything on place get a small bit of an already developed film-negative. It is a very cheap IR-filter layer solution. For a proper working proximity and light sensors it is necessary.
Put that piece of film under the top-row holes (do not cover the speakar holes!).

Step 4: Matching Color

Paint it to the right color. Luckily is simple black

Step 5: The Last Layer

OK, everything is almost perfect, but my finger still feel those cracklines. I bought a cheap iPhone screen protector layers from eBay, and covered the screen with that. It is cover the cracklines and also prevent to get dust in the light sensors and those tiny gaps between the glass and the plastic area of the screen.

I have to admit this is not an ultimate solution, but will be ok until I get a faulty iPhone with an intact screen