How to Find Installed Microsoft SQL Server 2008 Product Serial Key

Recently I had to find my original product key for MS SQL Management Studio 2008 in order to make a new installation, but I lost the key information I stored somewhere. So I tried to get the key from already installed product. First, I found the query for getting the key for Studio 2005, then following comments were including the key for 2008, but in 164-byte binary value… After more Googling, I found this great post at Branch Bits and it was sharing a program that converts this binary value to product key! Anyway so I used it and installed successfully.
Here’s the query that gets the serial number in binary format:

use master
exec xp_regread 'HKEY_LOCAL_MACHINE','SOFTWARE\Microsoft\Microsoft SQL Server\100\Tools\Setup','DigitalProductID'

And this is the source link.

And here is the link that you can get the project and use it for converting serial number:
Branch Bits – Finding SQL Server 2008 product key from an installed instance

P.S. For those who needs to find key of 2005 instance may use the free software named ProduKey. It works well for me.
Product CD Key Viewer
For further info, please refer to this question:
Question: SQL Server 2005 cd Key