Wi-Fi roaming specialist Boingo has added Sony Ericsson UIQ and Windows Mobile 6 to the list of mobile devices it supports with its roaming software.

The client software gives transparent access to any wireless hotspot on Boingo's roaming list, automatically identifying the hotspot and connecting to it. It is designed for use with the £3.95 a month Boingo Mobile package. This gives unlimited Wi-Fi usage, including VoIP, but only on handheld devices - it will not work with a laptop, the company said.

Boingo used the open source community to get its software ported, said Colby Goff, the company's senior VP in charge of network strategy and business development. It posted the client software on SourceForge and invited developers to port it to new devices. It already had versions for Series 60, WinMob 5 and Nokia tablets, and is targeting BlackBerry next, Goff said.

"We don't monetise the software - it's just there to make access to our service easier," he added.

He said that's why it's not a problem if customers choose to use other access software instead, such as the new DeviceScape v2 which can aggregate multiple Wi-Fi services in one client. He claimed though that Boingo's broad roaming coverage means most of its users shouldn't need another service.

Goff added that Boingo, which competes with other roaming aggregators such as iPass, is joining the Wireless Broadband Alliance, which should help it get closer to the big network operators.

The big challenge here is the number of relationships a company needs to offer a good spread of roaming, he said. Unlike the mobile phone networks, where there's rarely more than three or four in each country, there can be dozens or hundreds of hotspot operators.

However, he added that where the phone business is big enough to justify the existence of clearing houses who manage inter-network roaming, the Wi-Fi market is not - so companies such as Boingo must do it all themselves.

On the plus side, he said that most of its roaming relationships are unilateral, with the other party - for example, a hotel with its own hotspot - not needing roaming rights for its own users, and Boingo need only negotiate a wholesale rate with them, based on a usage forecast.