The code samples I demoed during my TechEd Middle-Tier apps with C# session have finally been uploaded onto GotDotNet.  Each sample has a readme.txt file which should give you more information for how to setup and run the samples. 

Demo #1 - Basic Serialization
The first sample is a very basic sample which shows how to return objects through web services, how to shape XML through attributes, and returning data through a DataSet in a web service.

Demo #2a - Binary Web Service
This sample shows how to return binary data, like an image, by using two different techniques, Base64 encoding and Direct Internet Message Encapsulation (available in WSE 1.0).  Because this sample can be might be difficult to explain, I've added a pretty picture:

Demo #2b - File Upload through a Binary Web Service
While ASP.NET made it much easier to upload files to a server when compared to classic ASP, I always found it really annoying to have to upload one file at a time.  To solve this, I created a web service that accepts an array of  (custom) file objects, consisting of a file name and an array of bytes Base64 encoded.  This upload web service can now be used by a variety of clients including Java applications for example.  To show the power of no-touch deployment, I used a Windows control with a label. When you drag-and-drop files over the label, the cursor changes to a "+" symbol, and if you release the mouse, the files are sent as an array of objects and uploaded onto a directory on the web service all at once.  I have a couple of thoughts on how I can improve this, including asynchronous upload with a status bar, FTP upload, and a dynamic client/server tree-view, but I just didn't have time.  I've included an explaining what's going on below:

Demo #3 Windows Services
The first sample shows how to use the FileSystemWatcher class in a Windows service to monitor a directory and log all file changes, renames, deletes into the Event Log.  It also includes a Windows Service installer which shows how to install a Windows Service.  The other sample shows how to start and stop a windows service directly from a mobile device (cell phone, RIM, etc) through an ASP.NET mobile web application. Relevant Resources:

Demo #4 ASP.NET Cache in DAL
This sample shows how you can leverage the powerful features of the ASP.NET cache directly in a middle tier Data Access Layer (DAL) by using the ASP.NET cache API. The DAL has two methods, one which retrieves using ASP.NET cache and the other without.  To exaggerate the speed differences, I also made both threads go to sleep for 1000 milliseconds when they hit the database and ran simple ACT scripts against both pages.  Relevant Resources:

That's all for now, enjoy :)