Funambol wants to offer a Blackberry for free to enterprise users, and an ad-supported mobile email service to every one else. It's based on open source, and in theory at least, allows enterprises and operators to do away with expensive Blackberry servers and handsets, and have email on regular handsets.

"Funambol is the largest open source mobile project," says Funambol chief executive Fabrizio Capobianco. "We are getting Blackberry to the masses, on mass market phones. Blackberry only reaches two percent of the market." With around three billion phones and two million email accounts, he reckons there's a big untapped market.

Open source gets round the problem of the number of different handsets, he says: "Device compatibility is the number one problem. In theory, in a mass market, you have to test every phone with every mail service. That's where open source kicks in." Funambol has contributors in every country who are happy to test and certify handsets. For a small fee, or to enable a service they want to deliver, they will make sure a given phone works with Funambol on a given mobile operator network.

"It's clear that in ten years, everyone will have email on their cellphone. That's the way we're going," he says. In Africa, some people's experience of email may be almost entirely on a phone: "There are more cellphones than houses with electricity. Some people can't have a PC at home, so their entire email experience outside the office may be on the mobile."

But how will Funambol make money? Not through the enterprise. That gets a "Community" edition with MySQL-style licensing targeted to enterprise. " If you are an enterprise, and you have an Exchange mail server, you can download our server, plug into the mail back end, and start pushing email to all users, not just to the CEO who has a Blackberry," he says. Funambol works on Razrs, Nokias, and even the Blackberry-toting CEO is catered for: there's a Funambol client for the Blackberry.

It may be free, but Funambol takes the enterprise seriously, and expects lots of take-up, perhaps through third parties who charge for support. "If you are using a Blackberry the cost is $50 per month. The cost saving can be enormous - and you can do it with phones users have already."

There aren't too many high-profile enterprise users, but Funambol is used by the French parliament, he says. MPs there wanted a Blackberry-like service, but did not want their official email going through RIM's servers in Canada.