Quite a few SVG Editors have come and gone over the last few years. DRAW SVG is a good example of one that survives. Also quite a few systems, such as those from Adobe, allow the resulting graphics to be saved as SVG.
Inkscape is a Free and open source vector graphics editor with the ability to import JPGS etc and convert to SVG and converts SVG to image formats.
Wikipedia has a Comparison of vector graphics editors page which is reasonably up-to-date.