I think these patterns are a very god idea. I have a few suggestions on how to polish them up for release:
The copyright year in the file header should reflect the years when the file contents is edited, i.e. for the new files it should be 2006.
All classes and methods should have user level comments. See other pattern files for examples.
The new patterns added to the PatternLayout should be documented in detail in the PatternLayout <remarks> section.
Is there any reason why you have not added a pattern for the AspNetSessionPatternConverter? aspnet-session?
The System.Web library isn't available on all platforms, you will need to exclude your new patterns from the build, and from the PatternLayout:
// .NET Compact Framework 1.0 has no support for ASP.NET
// SSCLI 1.0 has no support for ASP.NET
#if !NETCF && !SSCLI