Hi
you could use Opn source stuff like
Jmeter , or commerical Load
test suit like AppDev or Load runner.
There is a plugin for Eclipse Named TPTP
It could be helpfull if you want to test your server response specs.
I should menthion that TPTP works on Solaris too
you can find it here
http://www.eclipse.org/tptp/index.html