BT has over 500,000 SME broadband customers - and SME is increasingly interested in adopting solutions delivered as software-as-a-service. Hence BT and Microsoft have been working together to address this demand. Out of this work has come the BT Applications Marketplace which gives ISVs a quick and effective way to distribute applications to an audience of on-demand subscribers.
I would recommend you find out more if you have developed a SaaS-enabled application to the point where you want to do a market test or to start promoting a complete and tested service.
The official launch is Wednesday 25th. Head over there to find out more http://www.isvpartner.bttradespace.com/