SQL Server Express 2008 R2 comes in 32 bit and 64 bit versions. They are a free download at Microsoft's website. Make sure that the version of SQL Server comes with the database tools.
System Requirements
1.4 GHz 64 Bit CPU (64 Bit)
1.0 GHz PIII CPU (32 Bit)
1 GB RAM
SQL Server is advanced programming - It is suggested that you know how to program before trying SQL Server. SchoolFreeware has several tutorial series that will show you how to program.
Code Download
None - Follow the tutorial and SQL Server Express will be setup.