Microsoft and BT have signed a Web conferencing agreement that will see BT's audio conferencing technology added to Microsoft's Office Live Meeting, helping both grab a bigger slice of the expanding market.

The agreement expands on an existing arrangement BT held with PlaceWare before it was acquired by Microsoft last year. The technology combination will see lower costs and enable each company to get at the other's customers, a statement claimed.

BT will also use Live Meeting across its own organisation: while its European offices already use Live Meeting, its US offices often use market lead and main Microsoft competitor WebEx.

However, BT is playing it both ways and will continue to offer WebEx to its customers. According to BT Conferencing director Brenda Tretherne, it is also working with WebEx to link voice and Web conferencing services.

The Microsoft deal is one of several telco relationships Microsoft has renewed after its acquisition of PlaceWare. In February 2004, it announced a partnership with InterCall, and in May signed a similar deal with MCI. Microsoft representatives describe the relaunched partnerships as "deeper" than the previous arrangements.

The BT partnership aims "to drive the reach and adoption of Live Meeting globally. Telcos have great reach," said Jennifer Callison, director of Real Time Communications marketing at Microsoft. Callison described the BT alliance as a "high potential relationship".

"There is synergy in BT's integrated communications strategy and multiple Microsoft technologies," she said. "So we now have a relationship and potential commitments that wouldn't have been possible as part of PlaceWare."

Such relationships are a major part of Microsoft's efforts to steal market share from WebEx. Last year, WebEx boasted 67 percent of the Web conferencing services market share last year. "One of the top markets for Web conferencing is existing audio conferencing users," Callison said.

Forthcoming integrations between BT and Microsoft include linking audio controls between Live Meeting and BT to control things such as mute functions, and the capability to schedule Web conferencing and audio meetings - with a customer's preferred telco - at the same time.