Firefox 3 is now up to beta 5 and nearly ready for release!

Until version 0.2 of the sidebar code comes out, here’s how to get the sidebar working (and many other extensions) working in the beta version:

• Type about:config into Firefox’s address bar and click the “I’ll be careful, I promise!” button.
• Right-click anywhere. Choose New>Boolean. Make the name of your new config value extensions.checkCompatibility and set it to false.
• Make another new boolean pair called extensions.checkUpdateSecurity and set the value to false.
• Restart Firefox.

Thanks to this article on lifehacker for this useful trick!