Firefox 5.0 was released few days ago. But this time, its going to be a different experience for Ubuntu users. You don't need to add any additional third party repositories to get the latest Firefox update, its already available in your default Ubuntu 11.04 repositories.
No Need to Add Any PPAs for Firefox 5.0 in Ubuntu 11.04
The latest version of Firefox includes more than 1,000 improvements and performance enhancements. Firefox 5.0 is a very important release as far Mozilla is concerned and the new rapid release cycle is major shift in strategies. Google Chrome is growing at breakneck speed at the cost for IE and Firefox. Mozilla need to get its acts together and fast to stay afloat.
Ubuntu 11.04 Natty Narwhal users can rejoice. You don't need to add any external third party repositories to get the latest Firefox 5.0 update. It should be already available in your Ubuntu. Just 'check for updates' in Ubuntu Update Manager.