I found a great new tool, although it exists since 2005, for scripting Reporting Services.
Reporting Services Scripter is a .NET Windows Forms application that enables scripting and transfer of all Microsoft SQL Server Reporting Services catalog items to aid in transferring them from one server to another. It can also be used to easily move items on mass from one Reporting Services folder to another on the same server. Depending on the scripting options chosen, Reporting Services Scripter can also transfer all catalog item properties such as Descriptions, History options, Execution options (including report specific and shared schedules), Subscriptions (normal and data driven) and server side report parameters.
Download it here: http://www.sqldbatips.com/showarticle.asp?ID=62