Here are a couple recipes for glass cleaner.
1 Cup water
1 Cup Rubbing Alcohol
1 Tablespoon Vinegar
Mix together in a clean spray bottle. Use to clean glass surfaces.
Another recipe for glass cleaner:
1/4 -1/2 Teaspoon liquid detergent
3 Tablespoons Vinegar
2 Cups water
Put these ingredients into a spray bottle and shake well.
I've also been told that straight vinegar is a great window cleaner as well.