I guess could have just said go to the apple and click "about this mac" lol. I'm not at my mac right now so I'm Windows land lol.
Anyways, if you click on the "FireFox" link and it will take you to the download page. Once you install it try it out and see if it solves your hushmail problem.
Something else you can try is going to your Applications folder and see if you have a program called "Safari" I'm not sure if that will do it or not but you may want to try that first.
I'm quite new to OS X myself and am using version 10.3 so I'm not sure of the broswers included in other versions. The application name may be Netscape or another. But if it is Netscape download FireFox because that's the new name for the latest version Netscape I believe.
FireFox