.SVG - Scalable Vector Graphics
SVG is an open standard for vector graphichs similar to Flash. The advantage with SVG is that it can be edited with any text editor - the same way PostScript could. This is useful for software development and web site design.
About SVG files and how to create them by hand
Modern browsers support SVG files and extracted files can be opened with them.
Since SVG files are text based graphics files you can also view them with text editors like TextMate, TextEdit or Coda.
SVG graphics may also become a part of Microsoft Office as an alternative to WMF files.