Google Page Rank - New Domain / Link Structure Migration

Question

i've been tasked with re-organizing a pure HTML site into a CMS. if all goes well, the new site will eventually become the main URL, and the old domain will be phased out. the old domain has a decent enough page rank, and the company wishes to mitigate any loss of page rank for that. in looking over the options available, i've discovered a few things:

• it's better to use a 301 redirect when you're ready to make the switch (source).
• the current site does not have a sitemap, so adding one and submitting it may help their future page rank.
• i'll need to suggest to them that they contact people currently linking to them to update their links.
• the process for regaining an old page rank takes awhile, so plan on rebuilding links while we see if the new site is flexible enough to warrant switching over completely.

my question is: as a result of a move to a CMS driven site, the links to various pages will change to accommodate the new structure. will this be an issue for trying to maintain (or improve) the current page rank? what sort of methods are available to mitigate the issue of changing individual page URL's? is there a preferable method beyond mapping individual pages to their new locations with 301 redirects? (the site has literally hundreds of pages, ugh...)

ex.
http://domain.com/Messy_HTML_page_with_little_categorization.html ->
http://newdomain.com/nice/structured/pages.php

i realize this isn't strictly a programming question, however i felt the information could be useful to developers who are tasked with handling this sort of thing in addition to development of the site.

edit: additions in italics

Answer 1

If you really truly want to ensure that page rank is not lost, you will want to replace the old content with something that performs a proper 301 redirect to the new location. With a 301 redirect the search spiders will know that the content is moved and the page rank typically carries over. It also helps external links.

However, the down side is that after a certain period of time you just have to get rid of the old domains.

Answer 2

You can make a handler for HTML files and map the old pages to the new structure with a 301 redirect.