One way to copy a file from a remote client to a server via HTTP is to use an XML web service. Simply write a function in your service like:

Code:
<WebMethod()> _
    Public Sub SaveFile(ByVal buffer() As Char, ByVal destServerPath As String)

        Dim sr As StreamWriter

        Try
            sr = File.CreateText(destServerPath)
        Catch ex As Exception
            Throw New Exception("An error occured during file creation on the server", ex)
            Exit Sub
        End Try

        Try
            sr.Write(buffer)
        Catch ex As Exception
            Throw New Exception("An error occured while writing to the file on the server", ex)
        End Try

        sr.Close()
Then in your client app, pass the file stream along with the path to save it to.