T-Mobile has finally tied in all its Wi-Fi hotpsots across the US and Europe, offering a single, simple roaming option for wireless travellers.

From now, T-Mobile customers can access 4,100 hotspots in the US plus another 700 in Austria, the Czech Republic, Germany, the Netherlands and the UK with a single username and password. The service was announced at the 3GSM conference in Cannes.

The wireless broadband service, based on 802.11b, costs $10 (£5.37) for a 24-hour day pass to $40 (£21.50) per month on a month-to-month plan, demonstrating that the cost of Wi-Fi is continuing to fall.

In Cannes, T-Mobile also revealed plans for a multi-network service that will allow users to roam "seamlessly" across three different wireless networks: GPRS (General Packet Radio Service), WCDMA (Wideband Code Division Multiple Access) and Wi-Fi.

The hand-over between the networks will be automatic, according to T-Mobile International Chief Executive Officer Rene Obermann. The German operator is working with Cisco, IBM and Intel in a pilot project at various European universities that will enable students to roam across all three wireless broadband networks.

For the pilot, T-Mobile will provide the connectivity, offering students and professors bundled fees, which will include Wi-Fi vouchers for the operator's hotspots and preferential fees for GPRS and WCDMA networks. The operator will announce prices at the Cebit trade show in Hanover next month, according to Obermann.

Cisco will provide the wireless LAN infrastructure, while IBM will furnish the notebooks, using Intel's Centrino mobile technology. The pilot at Frankfurt University begins in April and is expected to last several months. A wider roll-out is then planned to cover over 100 universities in Austria, the Czech Republic, the Netherlands and the UK.