HttpFileServer is a simple REST-oriented file server with minimal requirements:
* PHP 5 (5.2 I suppose)
* web server (Apache will do)
* writable directory (this is where your files will be stored)
This is for the server part. For the client part you only need to be able to do HTTP GET and HTTP POST requests, so you're good with just wget in a batch script (or .NET application, or Ruby, PHP, Java - pretty much anything nowadays can form HTTP requests).
# store file on server - use HTTP POST
wget --post-file=file_to_send.txt http://server/index.php/path/to/store/file.txt -O -
# retrieve file - use HTTP GET