Hi,

Usually we use HttpWebRequest to post request soap message to web service whose based on Soap. and if you want to post data to another web site page using HttWebRequest, then you can refer to the following article.

http://www.worldofasp.net/tut/WebRequest/Working_with_HttpWebRequest_and_HttpWebResponse_in_ASPNET_114.aspx

You can also look into Web Services to accomplish it.

Hope this helps

Regards,
Peter