Python2 26

i=0;exec"print i;i+=2;"*51

independent discovery of @bitpwner's solution

Python 2 - 26

i=0;exec"print i;i+=2;"*51

Based on the tip on exec with string multiplication found at Tips for golfing in Python.

Python 3, 22 (Possibly not allowed)

If the challenge is "to create a python script which prints the even numbers from 0 to 100" and not "to create a python script which prints the even numbers from 0 to 100, newline separated", then the shortest solution is:

print(*range(0,101,2))

Remember, it's very important in code golf not to put any limitations on yourself you don't have to - do what the problem asks, and no more.

Python 2, 28

for i in range(51):print 2*i

Python 2 in *NIX, 24

os.system('seq 0 2 100')

If you need to add

import os

Then the total is 33 characters.

Python List Comprehension - 42

This uses a list comprehension, one trick to make it shorter is to multiply the index by 2 rather than going from 0 to 100 and a trailing if x % 2 check for even.

print'\n'.join(str(2*x)for x in range(51))

Edit: After separating values by newline it is by far not the shortest.

Python 2, 26 (possibly not allowed)

i=102
while i:i-=2;print i

It wasn’t strictly specified, in which order the numbers were to be printed.