The popular open source web browser, Firebox is biting into Microsoft’s Internet Explorer pie in Europe, and around the world, a web survey French-based firm, XiTi Monitor reported Wednesday.

According to its survey results conducted from Monday, July 2 to Sunday, July 8, 2007, Firefox’s usage share in Europe has risen to 28% for the week of July 2 to 8, 2007 vs. 25% from March 5 to 11, 2007 and 22% from July 3 to 9, 2006.

On top of 29 European countries and in pole position, Slovenia and Finland Firefox usage had surpassed 48%, 46% respectively, followed by Slovakia in third place with 41%.

With Internet Explorer popularity and usage, which still remains ahead in Europe, XiTi Monitor reported that ”Between July 2 and 8, 2007, the average visit share of a European country for Internet Explorer is in fact 67% whereas it was 74% one year earlier, from July 3 to 9, 2006. Opera arrives in 3rd, far behind Firefox, with a visit share of 3.5%”.

XiTi Monitor also highlighted worldwide trends in its Firefox usage survey, which confirms that the Oceanian continent still holds its position, being the largest Firefox user base with a rate of 29% from July 2 to 8, 2007, ahead of Europe at 27.8%.

Furthermore, the web survey firm also reported that Firefox is gaining ground in the other continents; however they are still below the threshold of 20%.

Surprisingly, XiTi Monitor also reported a very strong conversion rate to Firefox in South America, which has risen by 30% in just few months. Currently ahead of Africa at 15%, South America now stands at 16%.

Full report of Firefox’s new trend can be found here.