If you are using Firefox, you can go to “Help”, click on “About Firefox”. Most probably, you will get the update to Firefox 8.0. In this new version, you can perform Twitter search on the address bar.
For example, you can key in @xxxxxx on the address bar and Firefox will direct it to Twitter. Firefox also enhances its 3rd party add-ons by allowing you to choose which add-ons to activate (instead of automatic activation). There are other enhancements. You can check them out at their blog.
Click Here to Check Out Mozilla Firefox Update
or if you just want to update, click the below link to the update page (for Windows)
Click Here to Update Mozilla Firefox (Windows)