<p>I can handle the process that file part, but before I go crazy, has someone built a simple wcf service &amp; client (running under windows services or IIS) that I can use to upload a file, and download that file back? with the fewest lines of code? (C# or VB)</p>

<p>compression &amp; encryption would be cool, but i'll layer that on later!!</p>

<p>Thanks!!</p>

You should be able to do this fairly easily.  The service contract would probably look like this:
```
```
[ServiceContract]
public interface IFileService
{
  [OperationContract]
  byte[] ProcessFile(byte[] FileData);
}
```
```
The encryption part could be handled natively by WCF using transport level security.  I don't believe that WCF supports compression directly, but you could add that using the GZipStream class.
I have not built a file handling service as you describe, but I have built a service that handles byte array data that is passed back and forth between a WCF client and service.  It works just fine.