Update - For download links and related information see the Microsoft SQL Server: SQL Server Community Technology Preview Program. Another nice point worth noting is that along with the service pack we also get updated versions of Books Online and the Feature Pack, although the latter has no significant changes for SSIS, probably just some bug fixes.

An excert from the recently published What's New in SQL Server 2005 SP2, covering the main changes SSIS.

• The value of the BypassPrepare property of the Execute SQL task has been changed to True by default.
  
  In earlier versions, the value of the BypassPrepare property was false, which indicated that statements were always prepared. In SP2, by default queries are not prepared. This eliminates errors with certain providers when you try to prepare a statement that uses parameter placeholders ("?").
  
  For more information about the Execute SQL task, see Execute SQL Task.
  
  
• You can now use a combo box to select variables for properties of certain data flow components that require a variable name.
  
  In earlier versions, you had to type a variable name as free text to provide a value for properties that expected a variable name, such as the OpenRowsetVariable property of the OLE DB Source. The combo box now contains all the available variables, including system variables.
  
  
• The Lookup transformation now reports the final count of cached rows.
  
  In full cache mode, the Lookup transformation uses a function activated by a timer to report the count of rows that have been cached. In previous versions, the function did not always report the final count of cached rows. In SP2, the Lookup transformation provides a new informational message that reports the final number of rows that were cached in full-cache mode. This message appears in the Progress window and is logged by the OnInformation event.
  
  For information about the Lookup transformation, see Lookup Transformation.
  
  
• The Execute SQL task now has a ParameterSize property for string parameters.
  
  
• In earlier versions, the Execute SQL task failed when using an ADO.NET connection to execute a stored procedure that returned a string output parameter, because the size of the string parameter was set to 0 by default. In SP2, parameters used with the Execute SQL task have a ParameterSize property that can be used to allocate the memory required for a string output parameter. The Script component now raises an error when a <columnname>_IsNull property is set to True.
  
  The code generated by the Script component contains a <columnname> and a <columnname>_IsNull property for each input and output column. The intention of the <columnname>_IsNull property is to allow the user to specify a Null value for the column by setting the value of the property to True. To specify a non-null value, the user should assign a value to the <columnname> property. In earlier versions, if you set <columnname>_IsNull to False, the property was silently reset to True. In SP2, the Script component raises a warning message about the incorrect usage.