hello to every body i want to know that if i add PR6,7 links on my site which is PR 0 then it would give me some advantage or not .
yes, high PR backlinks that are not nofollow will get your site's PR increased if thats what you are after. i would however suggest you to focus on building ontopic links which will benefit you in the long run in terms of SERP ranking. PR doesn't increase your sites SERP ranking and dont drive any traffic to your site. it looks good on the toolbar tho...
It's somehow unclear whether you mean inbound and outbound links. If these are outbound links, that wouldn't affect your rankings. If these are inbound ones, the effect depends on what kind of links are those. Just pr means virtually nothing.