I’m really impressed that the SP1 for SQL 2005 is out so quick after the release of the CTP. The SQL Server Express Blog has a lot of information on the SP1 downloads. Also they have links to follow up information to help you get the most out of the product.
How to videos – there are 8 different sessions to get you started
New Technical whitepaper – Managing SQL Server Express with SQL Server 2005 Management Studio Express Edition
Starter Kits – Fully functional sample applications to help you learn SQL Server and accomplish common web development scenarios.