Angela! , by Oliver Pabst, is a natural graph editor with layout algorithms.
angela is an acronym for Angela is a Natural Graph Editor with Layout Algorithms. Use angela to create, edit and delete graph nodes and edges as well as save and load graphs. It can also generate Tcl/Tk applets so that the graph can be viewed as a stand alone application. There are input formats for PLING and GML and output formats for PLING, GML, and PostScript. LaTeX code can also be created.