1) Start Mozilla or Mozilla Firefox.
2) Type about:config into the address bar and press enter.
3) Once the page has loaded, type signed into the filter box.
4) You should now see one setting on the list, signed.applets.codebase_principal_support.
5) Double-click the line of that setting and change its value to true.
6) Restart your browser and go to the search page on IrcSpy.com.
7) Type the name of whatever it is you are looking for in the search box and submit.
Press any of the IRC links on the results page.
9) An Internet Security box should appear. Read what it says, check the Remember box and press Yes.

Happy XDCCing