hi i want to know that what is the effect of internal links in SEO for getting high PR.and in one page how many internal links can be provide.and if we provide more internal links than what will be the effects on SERP. thanks..
The point is for Google to find out which pages are more important on your website, like most templates have every page link to the home page and usually that's the most important page (unless you get a ton of links to another page in your site)
I know it helps for PR but havent seen any hard proof for SERPs. For instance if you have a PR4 site and put a sitewide link to another page there is a possibility that that page can get PR5 without any incoming links besides from the site. Its weird but I have seen it a few times.
Now days It's trend to build links to the internal or product pages. I haven't done any link building for my websites internal pages though but I have heardthat it helps.
Google webmaster guidelines state that the total links per page should be under 100 http://www.google.com/support/webmasters/bin/answer.py?answer=35769