If you need PR for a page, the page should be linked to all other pages and vice-versa to evenly distribute the PR. If PR does not matter for a page-you can forgo the linking structure and link as you like. A site i am doing SEO on has this situation-check out www.sierrainfotechindia.com. The FAQ page is linked to all other pages but does not have PR like the other pages, because the PR is distributed to FAQ1, FAQ2, FAQ3. Although these pages too should have PR and return it to FAQ-they also link to each other. This dissipates the PR and nullifies the PR received.

But the rule of thumb is that all your important-top level and 2nd level pages should link to each other.

Interlinking is useful as your homepage can only get first page rank in Google for a few keywords not all. In order to get maximum exposure on Google it is essential that multiple pages form your website can rank for independent keywords. Initially you will find that homepage is easiest to rank. However if you have good internal linking you will see that internal pages will also get a high PR in time and start to rank individually in Google for different keywords.

I would spread out where your incoming links come to. Go with most relevant when possible Having links to e.g. articles is great since they also then stand a better chance in search engine result pages.

The pages that I have lost page rank on are only 1 deep.. and are on every page of my site. It is all the links in the top menu that have lost rank. I am not worried but am very interested in learning how to control it myself.

It always good link internally, apart from Google liking it, it also heps site visitors find their way around. Its gives your user a website which is easily and entirely navigable from one single page to the other.

Techniques of internal linking includes:
deep link directory submission
Internal linking in your website.
Putting internal link url in forum signature.

follow up with danny shez right

Linking to internal ages on your website certainly has its advantages. It will help improve the rank of the internal pages on search engines. This will be great help for SEO as different pages on the website can be ranked for different keywords as such the overall visibility of your website on search engines will certainly improve a lot if you link back to internal pages. The page rank for the internal pages will also improve as a result of deep linking.

It sounds like alot of work.
Do you only get PR if there are links to your page. I have pages with PR that are popular pages but have people really created links to them?

It is a lot of work... a long, continuous work.

If I'm not mistaken, having other sites link to your site pages is part of the factor that determines your pages' PR. You can check your backlinks to see the sites that are linking to you.

IT ALL DEPENDS UPON YOUR SEO GOALS!

If you have targeted keywords to internal pages, you must have to go for "deep linking strategy" otherwise your HOME page can only hold 2-3 keyword phrases. You internal pages are optimized for other keywords which need to get ranked and could only be achieved if link building is done for them as well.

Thank you