Google has launched a tool that lets users synchronise browser settings across multiple computers - but only if they are using Mozilla's Firefox.

There is no version for Microsoft's Internet Explorer, of the Google Browser Sync tool, which lets users maintain the same bookmarks, visits logs, saved passwords and persistent cookies in all their copies of the Mozilla open-source browser.

For continuous synchronisation, users have to install copies of the Google Browser Sync on every computer where they use Firefox, Google announced in its official blog.

This free tool also "remembers" the tabs and windows users had opened the last time they used Firefox, and gives them the option to open them again. One downside is that the tool updates settings every time Firefox is launched, which will increase the time it takes a browser to open, Google warns.

Google Browser Sync works with Firefox 1.5 and newer versions. It doesn't support Microsoft's Internet Explorer (IE), Opera or the Mozilla Suite, which includes the Mozilla Navigator browser.

Google has a close relationship with Mozilla that involves technology collaborations and cross-promotion efforts. This is in marked contrast to the adversarial and often acrimonious relationship between Microsoft and Google, which compete in search, online services and, increasingly, in desktop and hosted software.

Browsers in particular are a contentious area between Google and Microsoft because they are an entry point to Web search activity. Recently, Google has complained that version 7 of IE, now in beta, contains an embedded search box set by default to use Microsoft's search engine - although a drop down menu box includes other options.

However, some have criticised Google for hypocrisy, since its search engine is the default choice in the embedded Firefox search box.

Firefox is a thorn in Microsoft's side, because it is the most credible competitor to IE in years, holding an estimated 10 percent market share.

In April, Google caused a stir when it promoted Firefox on its home page, a rare move and one clearly intended to help Firefox grow its market share. Google also includes Firefox in its Google Pack, a free, downloadable software suite that it distributes and that includes products from Google and other vendors, including Adobe and Symantec, but not Microsoft.

More information and download instructions for Google Browser Sync can be found at: http://www.google.com/tools/firefox/browsersync/index.html.