>I need to develop an interface to a web-based application that communicates via http (and later https) protocol. The data itself will be a combination of standard HTTP parameters, in addition to an XML document when submitting messages. [...]
>What is the best way to incorporate sending and receiving these type of messages from within my existing VFP5 application. Is there a COM or ActiveX module that I need to look into, or what can else can you suggest?

Microsoft exposes http functionality through WinINet.dll: http://msdn.microsoft.com/library/default.asp?url=/workshop/networking/wininet/wininet.asp which is callable by VFP5