MSDN information aggregator site for Reporting Services 2005. 

Important downloads for Reporting Services 2005:

SP4:

• SQL Server 2005 SP4 Cumulative Update #3 (build 9.00.5266)
• SQL Server 2005 SP4 Cumulative Update #2 (build 9.00.5259)
• SQL Server 2005 SP4 Cumulative Update #1 (build 9.00.5254)
• SQL Server 2005 SP4 RTM, Express Edition RTM (build 9.00.5000)

SP3:

• SQL Server 2005 SP3 Cumulative Update #15 (build 9.00.4325) 
• SQL Server 2005 SP3 Cumulative Update #14 (build 9.00.4317) 
• SQL Server 2005 SP3 Cumulative Update #13 (build 9.00.4315) 
• SQL Server 2005 SP3 Cumulative Update #12 (build 9.00.4311) 
• SQL Server 2005 SP3 Cumulative Update #11 (build 9.00.4309)  
• SQL Server 2005 SP3 Cumulative Update #10 (build 9.00.4305)  
• SQL Server 2005 SP3 Cumulative Update #9 (build 9.00.4294)   
• SQL Server 2005 SP3 Cumulative Update #8 (build 9.00.4285)    
• SQL Server 2005 SP3 Cumulative Update #7 (build 9.00.4273)   
• SQL Server 2005 SP3 Cumulative Update #6 (build 9.00.4266)  
• SQL Server 2005 SP3 Cumulative Update #5 (build 9.00.4230)   
• SQL Server 2005 SP3 Cumulative Update #4 (build 9.00.4226)   
• SQL Server 2005 SP3 Cumulative Update #3 (build 9.00.4220)   
• SQL Server 2005 SP3 Cumulative Update #2 (build 9.00.4211)   
• SQL Server 2005 SP3 Cumulative Update #1 (build 9.00.4207)   
• SQL Server 2005 SP3 RTM (build 9.00.4035)  

SP2:

• SQL Server 2005 SP2 Cumulative Update #17 (build 9.00.3356) - Final CU for SP2
• SQL Server 2005 SP2 Cumulative Update #16 (build 9.00.3355)   
• SQL Server 2005 SP2 Cumulative Update #15 (build 9.00.3330)  
• SQL Server 2005 SP2 Cumulative Update #14 (build 9.00.3328) 
• SQL Server 2005 SP2 Cumulative Update #13 (build 9.00.3325) 
• SQL Server 2005 SP2 RTM (build 9.00.3042) 
   
• RS Add-in for SharePoint Integrated Mode (SP3 download, SP2 download) 
• SQL Server 2005 Books Online (December 2008 Update)

Last page update: March 27, 2011.