Reporting Service rendering web part for share point is available at %\Program Files\Microsoft SQL Server\90\Tools\Reporting Services\SharePoint when SQL Reporting Service 2005 is installed.
Install the above web part in share point with stsadm.exe. It consists of two web parts, Report Explorer and Report Viewer. Report Explorer is basically for listing the reports available in the reporting service in the specified folder (configuration of web part) and Report Viewer web part is for rendering report. Drag both web part in one of the sharepoint pages
Enter the report manager url in the "Report Manager URL" property of Report Explorer web part.
Enter the folder name in the "Startpath" property of Report Explorer web part so that it will list only those reports in that folder. (It can remain empty)
In design mode of the page, go to properties of Report Viewer web part and select
Connections - > Get report from -> Report Explorer.
Now, click one of the reports in the Report Explorer web part listing and find the report rendered in the report viewer web part