SQLCat has a great blog post about installing SSRS with Sharepoint integration:
This technical note describes how we designed and implemented a business intelligence solution that utilized a server farm containing Microsoft® Office SharePoint® Server 2007, Microsoft Office PerformancePoint® Server 2007 Monitoring Server, and Microsoft SQL Server® 2008 Reporting Services in SharePoint mode, all running on Windows Server® 2008 R2 and with all servers and applications configured for Kerberos authentication. In this technical note, we discuss the design requirements for this business intelligence solution, its logical architecture, the challenges we faced in architecting and implementing this solution, and our resolutions to these challenges.
wish we had this sooner, implementing this is NOT easy. See also my colleague Marc Valk excellent blog post about Sharepoint and SSRS integration over multiple servers (not the default all on one box) with the famous double hop issues and how to fix them. Read it here:
http://www.marcvalk.net/2009/04/sharepoint-and-ssrs-integration/