1.My blog was mentioned on other big blogs that have PR 6&7.Ok now the link to my article is on the first page that is PR6 for example.But after some time the posts will go in page 2,3 ... because those websites post new stuff every day.So can I say that I've got a Pr6 or 7 link ? 2.If I've got links from other sites just for one of my pages ... this will affect the whole site, and the main page ?
1. No - you don't have a permanent link on a PR 6 or PR 7 page. Even if it counted, if you're talking about a high PR ranking from Google then you can't rely on link from just one source as if they aren't in a very closely associated industry or have many links out on their page then your link wouldn't count for much. 2. As long as if you have decent text navigation in place on your site then you should get the 'PR trickle down effect'.
Sure, you've got a PR6 or 7 link - but only until it shuffles to page 2 and then it becomes PR0. Unlucky.
Page rank first of all makes no difference in rank at all, the only time it helps is in telling you if one of the links you got or purchased is important to Google. That link will throw some love your way, but to your question no you do not have a pr 6-7 link. If you want some though let me know, I have several services which will help you out!