References :
http://blah.winsmarts.com/2007-12-SharePoint_and_SQL_Server_Reporting_Services_-_Installation_and_Setup.aspx
http://mikewalsh.bilsimser.com/PermaLink,guid,3ff1194c-3b48-4f35-9797-a03327db8d00.aspx
http://www.microsoft.com/downloads/details.aspx?FamilyID=ae7387c3-348c-4faa-8ae5-949fdfbe59c4&displaylang=en
http://www.microsoft.com/downloads/details.aspx?familyid=1E53F882-0C16-4847-B331-132274AE8C84&displaylang=en
http://blogs.msdn.com/sharepoint/archive/2007/02/19/microsoft-sql-server-2005-sp2-reporting-services-integration-with-wss-3-0-and-moss-2007.aspx
http://technet.microsoft.com/en-us/library/ms159704.aspx
http://blog.rafelo.com/2008/08/sharepoint-and-ssrs-deep-integration.html

Points to remember:
1. Install reporting services on MOSSReports ( Central Admin Box ?? ), and also have the Business Intelligence Development studio installed either on the same machine, or on a seperate developer box. Service Account Configuration while installing Reporting Service Domain user account -- System Account of the Central Admin should be good Use the same account throughout

2. Install SQL Server SP3 on your SQL Server & MOSSReports.

3. Before installing the add-in
a. You access this page by "Reporting Services configuration"
b. Setup Report server VIRTUAL Directory even if it shows green.. may not be used anywhere though :)
c. When you do there is a question mark next to SharePoint Integration. This it says is because you haven't specified a Database for reports. You go to Database Setup and see that there is a database specified for Reports. You try just saving that. I can assure you it's not going to be enough. Instead what you need to do is to create a NEW Database for reports or amend the existing one (which SQL Server 2005 Reporting Services installed for you which the writer of the paper knows you have done ....) I created a new database just to be 100% sure.
d. That new database needs to have "SharePoint Integration" selected (the same page where you create it - i.e. in the Database Setup part of the Configure Report server page).
Now finally you have a tick next to SharePoint Integration and your own "Configure Report Server" page looks like the one in the Team Blog.

4. log in as the user used to install MOSS 2007 and only then install the Add-In on the SharePoint 2007 web front ends.

5. The next step is described in WinSmart.com (http://blah.winsmarts.com/2007-12-SharePoint_and_SQL_Server_Reporting_Services_-_Installation_and_Setup.aspx) as "you must set each of the options ... as follows" -- from the Central Admin Manage integration settings – To configure the Report Server Web Service URL and Authentication Mode (either Windows or other trusted account). Grant database access – To configure the name of the report server database server instance name. Set server defaults – To configure report server timeouts and other options.

6. Execute the following command on all WFE's - stsadm.exe -o addwppack -filename "C:\Program Files\Microsoft SQL Server\90\Tools\Reporting Services\SharePoint\RSWebParts.cab"

7. the Report Server Windows service account and the Report Server Web service account -- manually grant access to
Add the accounts to the WSS_WPG Windows group on the Reporting Services computer.
Add the SQL database login to the following database roles: db_owner role in the WSS Content database WSS_Content_Application_Pools role in the SharePoint_Config database

8. The following step may be already packaged ..Go to Site collection features, and activate the "Report Server Integration Feature".Create two document librariesa) One a simple document library, call it "Reports" <-- this is where we will store our reports.b) One a data connection library, call it "DataConnections" <-- this is where we will store our data connections

9. the Connection source.. user SQL Connection rather than Windows authentication