plz help me for using mshtml in vb.net?

[ziaiz]

hi;
i want to extract data from websites i have gone throug some examples on deofferent sites using MSHTMLDocument but i m unable to understand following:
1. mshtml object model?
2. ipersiststreaminit interface?
3. can i use mshtml without using com introp?
4. i want to itrate into tags like <table> and <p> and if and table tag contains <p> and <p> contains data then i want to extract that data. (i mean how do i itrate into tags under the tags?
5. and one thing more the differences between HTMLDocument and HTMLDocument2,3,4 etc.
plz help me.