I set 1 weblog in my project called “Event”. In this weblog, I will allow Registered Member to post an Event information. I modify Comments template from template Library for this purpose.

Within this Event weblog, I need an Entry Date and Expiration Date Form ( Just like the Date Tab in the Control Panel), so that any event posted, will be expired once the information is expired. A registered member will have ( must) enter the expiration date.

How can I achieve this?

Having users create new entries (not comments), you can use the Stand Alone Entry Form.  That includes the ability to set the dates.

I have studied the Stand Alone Entry Form. Thank you. My question is, Can (1) member/registered user who has not login yet and (2) a non registered member/a guest, able to see a news/comment which has already been posted before?

Thanks

Viewing of the entries is done by anyone with access to the output template.  But posting via the stand alone entry form is only for logged in users.