embed an R console into a web-page?

Maybe try something like this 
http://www.askapache.com/ajax/php-and-ajax-shell-console.html ?
But there will some security questions...
The simplest way I see is OpenSSH + R + Putty (for Windows Users), but 
in this case you get some troubles with instant graphical output.

Best regards,
Zhan A Chubukou
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Gomel State Medical University
Department of Pathological Physiology
246000 Belarus, Gomel, Lange str. 5