Several sources report that the soon to be released Beta of Firefox 3.1 will support Private Browsing.
Firefox 3.1 is said to support Private Browsing that allows you to surf incognito.
The feature that more or less allows users to surf "unnoticed”, is already part of the Internet Explorer 8 (Beta 2) and Google's Chrome.
Private Browsing enables users to surf on websites without having the URL recorded in the browser history. Cookies aren't created either. Downloaded files don't appear in the download history and the browser doesn't remember passwords that are typed.
The Beta of the Firefox version 3.1 is expected to be released in October.