Beta 5 of Mozilla's open source Firefox 3 browser is now out boasting no less than 750 improvements over the Beta 4 release. 

Among all those improvements are some that users will likely notice right away. In terms of speed, Mozilla developers have made improvements to the JavaScript engine in Firefox. They claim that Firefox 3 Beta 5 will now run web based Ajax apps like Google Mail twice as fast as the current Firefox 2.x branch.

Mozilla has also improved the overall integration with Windows, Mac and Linux desktops to have a more native user look and feel in terms of icons and toolbars.

There are also improvements to the  Places engine (which is the new bookmarking infrastructure in Firefox 3).  The Places Organizer has been further improved in Beta 5 to make it even easier search through both bookmarks and browsing history.

The Beta 5 release is the last beta for the Firefox 3 release train.  The next step is a Release Candidate (RC 1) expected at some point in the next several weeks.