You can now export a single snapshot from a virtual machine.  This works by selecting the snapshot in question and then selecting Export… from the Action pane.  We will merge all the snapshot disk data into a single new virtual hard disk – and the resulting exported virtual machine will look like a virtual machine with no snapshots that is identical to the snapshot you selected.  Note that the virtual machine needs to be turned off in order to perform this operation.

Snapshot AVHD files are now created in the same directory as their parent VHD files.  Their names have also been updated to include the name of the parent virtual hard disk.  Both of these changes make it easier to identify and group snapshot files.

Name of the AVHD that is associated with snapshot - When you open the settings for a virtual machine snapshot and look at the hard disk settings – you will see the name of the AVHD that is associated with that snapshot.  This helps you to map AVHD files to specific snapshots.

You can now edit AVHD files in the edit VHD wizard.  This means that if you want to manually merge AVHD files to a new VHD to give to someone else – you can (note: be careful as you can cause problems if you merge back into the parent in this case).

You can now directly attach an AVHD file to a virtual machine.  This is very handy if you have lost your virtual machine configuration and need to get data off of a snapshot file.

Source: http://blogs.msdn.com/virtual_pc_guy/archive/2009/06/18/changes-to-virtual-machine-snapshots-in-windows-server-2008-r2.aspx