Check out this 4 minute video on a very useful feature in the 2008 vol 2 release. The video/screencast shows you how to enable editing using the LinqServerModeDataSource component. Check out this video To get a good overview of the LINQ Server Mode support.
The Server Mode feature is one of the most unique and intelligent approaches to dealing with large datasets. And now it’s even more flexible with support for editing so you won’t need to write your own events to save, insert, and/or delete. Three new properties were added to the LinqServerModeDataSource to support these editing functions.
If you still need to do custom updates even with the new features, then you can still use the RowUpdating, RowInserting, and/or RowDeleting events. Watch the video and let me know how it changed your life. 
