Webdot Graph Server - http://www.research.att.com/~north/cgi-bin/webdot.cgi/

Webdot is a server program that converts graphs described in the DOT abstract graph description language into GIFs that can be included in HTML pages. The graphs can contain mouse-sensitive nodes simply by giving the node a URL attribute, so there is no need to worry about x-y coordinates

Webdot can serve a graph from a (dot source) in more than one format:

 text/plain(dot source) 
 image/gif 
 text/plain(imagemap) 
 application/x-pcl 
 application/x-hpgl 
 application/x-dot 
 application/pdf(PDF) 
 application/postscript(PS) 
 application/postscript(EPSI) 
 application/x-tcl(Tclet) 
 application/x-mif(FrameMaker) 
 x-world/x-vrml(VRML) 
 application/x-vtx(VisualThought) 

 By StephenNorth  - http://www.research.att.com/~north/