SQL 2008 Express Editions and Service Packs -( from Microsoft site )

1. Microsoft® SQL Server® 2008 Express with Advanced Services 

2. Microsoft SQL Server 2008 SP2 Express Edition Service Pack 2 

3. SQL Server 2005 Backward Compatibility-2





Extra items :

Microsoft SQL Server2008 R2 RTM - Express with Advanced Services 
Microsoft® SQL Server® 2008 Express Edition Service Pack 1 
SQL Server 2005 Backward Compatibility-1




(Click on the option for download page in Microsoft Site)