“so would it be better to link to all your inside pages from the main page?”
“Better for what” is an important question, and the answers can be all over the board. If you only care about main page PR (a major mistake in my opinion) then you would go down one road. If you were trying to rank for dozens of pages, then you would do other tactics.
“or better to have a single link from your main page taking surfers to a page marked say, site map, and having surfers do their navigation from this page, as opposed from the main page.”
This is usually not good. It IS good to have a site map linked from the main page, which links to all pages (or to all main sections if your domain is huge), but each time you link the PR you pass goes through a “dampening” effect. You lose about 15% of your link pop each time youhave a stop in the linking process. So comparing:
A links to B which links to C
to
A links to C
in the second example the PR of C would be somewhat higher.
So, don’t make you PR make uneccessary stops.
“and then as I understand it; you’d want every inside page to link to your main page (this a one-way link), is that correct?”
Assuming you want you main page to have the highest PR is can, yes all pages should link to it. But it’s not that simple. If pageZ links back to the main page and has five links in total on that page, it will deliver back to the main page a lot more PR than if it has 100 links on it… even if thos 90+ other links go to pages on your domain that link back to the main page, your are again dampening the flow of PR back to the main page.
PR is like a river that rolls throw your site(s). You can direct that river, make bigger resevoirs and smaller ones, make all subpages about equal in PR or (usually much better) have some sub pages that have higher PR than other subpages. It really depends on what you want to accomplish.
In general, a lot of gambling domains hemoragge PR and don’t recycle what they have back through their domains very well.
Getting back to the first question, size of a domain matters in answering this. What to do with a 20 page domain is different than a 200 page one or a 20,000 page one. One bedrock rule of thumb is to not have more than 100 links on any page, but beyond that you can make a few sensible choices based on where you want to focus your PR.