Visit this web address: http://www.mozilla.com/en-US/firefox/all-beta.html Select the language that is yours and the operating system that you use. Click on download that you want, and save it to your desktop or to a folder where you can easily find it.
Step2
Open the file that you just downloaded, it should be Firefox Setup 3.0 beta 2.exe (windows version) If you have a Firefox Browser open, then close it and double click the downloaded file to install Firefox 3.0. It may prompt you to install any updates when it first starts up, answer yes if you want the updates. The browser will start up and work as it was before. All your bookmarks will transfer over.
Step3
Thank you for helping test Firefox 3 Beta 2! This release is being made available for testing purposes only. You should read the release notes before getting started.
We want to hear all of your thoughts about this beta, especially if you encounter broken sites or other web weirdness. Drag this feedback button onto your bookmarks toolbar and click on it when you have something to tell us. We'll be waiting to hear from you! (Or, if you'd prefer, you can file a bug.) I did notice that some features went away as the beta version is too new such as the dictionary, but I misspelled dictionary and the built in spell checker caught it. I love technology!
Tips & Warnings
This is a beta product and may have unresolved issues, betas may unexpectedly crash and if stability is an absolute requirement then stick with non-beta software.
Install beta software at your own risk, I am writing this article in Firefox 3.0 with no problems.