We've used vinegar for killing weeds around the garden, for several years now. It's a great way to get rid of weeds in cracks in cement or in a paved driveway. You can pour it on directly from the jug or put it in a spray bottle (use full strength). Just a word of warning, if you don't want it to die, then don't go near it with the vinegar. If using in a flower garden, be careful around the plants you want to keep. The vinegar will leach to the other plants through the roots and kill them, so it may be better to pull these by hand.
Hope this helps! Good luck!
Put straight vinegar into a cheap garden sprayer ($12) & spray this onto your weeds. You can also pour the vinegar right on to the soil to kill the roots and stop everything from growing there in the future.