The default memht header defines a single description of any page of your site.. since meta descriptions are utilized by search engines to apply a brief description of the page listed in the results.. and people will see different pages when they search for your site.. is it possible to apply different meta keyword/descriptions for each page?

yes

Admin Panel => System => Pages => Edit

thanks, it's cool.. Is it also possible to have a different meta description/keywords for each post?

It's possible but too complicated