TechNet Magize published an article which provide overview of SQL Server Migration Assistant (SSMA) features and how it can be used to support database migration to SQL Server.
SQL Server: Manage the Migration describes the main feature area of SSMA including migration assessment, converting database schema, migrating data, and testing database migration. If you prefer to watch video presentation, I recommend to watch the recording of the SSMA session at 2011 North America TechEd available from Channel 9.