I used the following code for posting/uploading binary data (example: upload a file for an email attachment in webmail). It can also be used to send MMS messages to an Internet MMS Gateway.
Code is in VBScript which can be run without the use of additional components.

Example1 (upload)
Example2 (mms)

If you however like to use a component, try ASPFusion‘s AdvHTTP. You don’t need all the code and don’t need to bother about the fact that VBScript is not BinarySafe.