Free Upgrade Advisors / Best Practices Analyzers
These tools from Microsoft can be instrumental in cleaning up your systems and finding issues *before* the day of the upgrade. I'm including the SQL Server 2005 versions, but if you're just planning your upgrade to 2005 now, I'd suggest re-thinking toward 2008 or 2008 R2. The last service pack for 2005 is due out later this year, and the next major version of SQL Server is probably about a year after that. Note that there is no SQL Server 2008 Best Practices Analyzer, at least that I could find.
SQL Server 2005 Upgrade Advisor
SQL Server 2005 Best Practices Analyzer
SQL Server 2008 Upgrade Advisor - download x64 - download x86
SQL Server 2008 R2 Upgrade Advisor - download x64 - download x86
SQL Server 2008 R2 Best Practices Analyzer - download x64 - download x86
(For some advice about the R2 BPA install, see this post from August)
Free Documentation
Books Online is the official go-to documentation for SQL Server, but you don't have to have a SQL Server license to use it. You can choose to download the application (or install it as part of setup) and keep it up to date, or use the web-based version.
SQL Server 2005 Books Online - or download
SQL Server 2008 Books Online - or download
SQL Server 2008 R2 Books Online - or download
Free Feature Packs
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