Yeah have seen that only issue is it's only for Opera browser. However Google[1] and Mozilla[2] are both working on remote debugging solutions that will allow you to have true remote debugging abilities, like attaching break points and do a whole bunch of really cool stuff that isn't possible with just JavaScript. There is also the weinre project[3] which has some huge potential.
[1] http://code.google.com/p/chromedevtools/wiki/ChromeDevToolsP...
[2] http://getfirebug.com/wiki/index.php/Crossfire
[3] http://pmuellr.github.com/weinre/