My company took some old php application over. Due to our preference to ASP.net and to the lack of any documentation from the previous developer, we do not want to spend much resources on developing in PHP. For implementing new features, we will create an Asp.net application that has the same look to the user. We want to develop a kind of 'coexisting' web application. Therefore we must share sessions between an PHP and an Asp.net webapplication project, because there is a usermanagement involved with an existing MySQL database.

(e.g. link 'A' directs to the PHP website, and link 'B' directs to the asp.net application)

How can we share the session between and PHP and an asp.net application?

And does anyone have a hint for this 'coexisting' thing, that might be useful in development?

Edit: IIS 6 would be our targeted server, altough IIS 7.5 would also be an option