Netscape founder Marc Andreessen is backing a new browser dedicated to browsing Facebook, called RockMelt, according to rumors we've heard from reputable sources. A semi-independent desktop client for Facebook? Doesn't seem far fetched at all.

The software isn't publicly available or being discussed yet, but we've gotten our hands on an early build and had a look at the front door after download. Robert John Churchill, who was the principal engineer for Netscape Navigator, is the principle engineer for RockMelt as well.

The project is surrounded by a team of engineers from Andreessen's last giant sale, infrastructure company Opsware, and from HP, which bought Opsware for $1.6 billion in 2007. Andreessen and Opsware co-founder Ben Horowitz launched a new venture fund for web startups last month. Andreessen has not personally invested in Facebook but is the fourth member of the Facebook Board of Directors, along with two of the company's earliest investors and founder Mark Zuckerberg.

We haven't confirmed Andreessen's involvement in RockMelt, but we hear he's backing it and all signs point to him. He hasn't responded to our inquiries yet, but we'll update this post if he does.

The project is actively recruiting staff but we're hearing rumors that current Facebook staff may be working on it as well, including Firefox creator Blake Ross and Facebook iPhone app developer Joe Hewitt. Ross and Hewitt came to Facebook two years ago when their secret project called desktop/web project Parakey was hire/acquired by Facebook. (See also VentureBeat for good coverage of that project and deal.) Ross and Hewitt's participation is the least verified part of this story so far, but it sure would be great if they are pitching in. (Update: Dan Frommer caught a denial by Hewitt on Twitter yesterday, so there you go.)

RockMelt also has its own URL shortener, me.lt, though mention of the new browser was removed from that page earlier this week.

Why does the world need a Facebook browser? A cynical and sarcastic answer would be "because Facebook is the internet and the internet is Facebook." It's a little harder to be too cynical, though, when you look at the team of people who appear to be working on the project. These are people who have done a lot for the open web. Hopefully RockMelt will be a game changer in the same spirit, but we'll keep you posted as we learn more. It might seem outlandish, but desktop software dedicated to serving Facebook and perhaps integration of other sites with Facebook, could go over very well with millions of people. We'll have to wait and see what RockMelt has planned.

RockMelt could be a way to browse the web with Facebook ever-present, as well, instead of being a client for Facebook. We just don't know yet. This may be part of but could instead be contrary to the growing storm of support building for a distributed framework for social networking.