If you are trying to create extended stored procedures in SQL Server 2008, you will probably have read the BOL article here:

Creating Extended Stored Procedures

Hopefully you will have noticed that this feature is deprecated, and so firstly you’ll only be using this functionality for legacy requirements. That said you may have noticed that you will require the file opends60.lib to be able to create your extended stored procedure DLL. You may have noticed that you cannot find this after installing SQL Server 2008 (even if you have installed the SDK).

The default location for the SDK directory in SQL Server 2008 is here:

C:\Program Files\Microsoft SQL Server\100\SDK\

However it does not contain the opends60.lib. If you need to acquire a copy of this file, currently you need to obtain it from an alternate source, namely a previous version of SQL Server SDK or from an install of a previous version of visual studio. For example the x64 version of the file can be found in the SQL Server 2005 SDK directory here:

C:\Program Files\Microsoft SQL Server\90\SDK\Lib\x64

You should be able to use one of these other versions instead.