Code Metrics are completely new and exiting functionality in VS 2008 but its only available on Team Foundation based visual studio versions and there are many poor folks who do not have access to those.
For them, there is a custom add-in for Visual Studio 2005 (which works with Visual Studio 2008 as well) that counts LOC using customizable counting rules. The tool is written by MicrosoftIT in partnership with Microsoft Research. You can download LOC counter from the following link:
Download LOC Counter
70c747b1-b361-455c-ae33-7afe692c8a4a|0|.0
vs 2005, vs 2008