LINQ to SQL Entity Base includes change tracking support in a "disconnected from data context" mode.
LINQ to SQL Entity Base also supports automated re-syncing of entities to a data context. This includes all entities under a entity tree which is basically all parent --> child type relationships.
Other features also include:
--> Querying across entire LINQ to SQL entity tree for an object(s) with the use of LINQ syntax.
--> LINQEntityID property for each LINQ entity object for unique identification and bookmarking of a LINQ entity.
--> Support for Serialization (via DataContractSerializer) for use in n-Tier environments using WCF.
http://complexitykills.blogspot.com
http://www.codeplex.com/LINQ2SQLEB/Release/ProjectReleases.aspx?ReleaseId=12556