R help - Sep 2009 - Alternatives to Rgraphviz -- request suggestions

Dear R-helpers,

Can anyone suggest a useful alternative to Rgraphviz?  I am trying to 
create fairly simple graphs showing the structures of a hierarchical 
cluster analysis or of a structural equation model.  That is, I need 
to be able to control the shape (rectangles vs ovals) of a limited 
number  (<  several hundred) of nodes, connect them with edges that 
have values (usually numeric but sometimes text) and produce pretty 
output.

I want to be able to force nodes to be on side or the other of the 
graph (sometimes, some on one side, others on the other side) and to 
minimize the number of edge crossings.

I have been using Rgraphviz as a recommended but not required package 
for my psych package for several years but remain frustrated by the 
difficulties some users have installing Rgraphviz from BioConductor 
as well as by recent problems with graphviz itself (it will not 
install on Snow Leopard for the Mac).

When Rgraphviz works, it is wonderful.  However,  PC users in 
particular seem to have problems installing it and now with Snow 
Leopard I can not get it work either.


Does anyone have  a recommended graphics packages that has at least 
some of the features of Rgraphviz (and hopefully, fewer of the 
difficulties).

Thanks to all for your suggestions.

Bill

-- 
William Revelle		http://personality-project.org/revelle.html
Professor			http://personality-project.org/personality.html
Department of Psychology             http://www.wcas.northwestern.edu/psych/
Northwestern University	http://www.northwestern.edu/
Use R for psychology                       http://personality-project.org/r
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