301 Redirect And Pagerank Options

[ephricon]

There was a little discussion about 301 redirects in another forum, but that sort of sprouted out of another topic... Anyhu, here's my question and situation...

The Situation
My largest client is a respected professional association that had a decent website up at URL1 (a certain URL the site had been at for a few years). The site has a PR of 6.

A few months ago we decided to redesign the site (it much needed it) and also move the site to a new domain name that we viewed much better as it is the acronym of their name and thus better suited as a domain than the old one.

Not only did the design and domain name change, but I am not running the site largely w/ asp and a database, whereas before it was completely static. Thus, all the filenames have changed (not just extensions but also file names). As of right now the new site only has a PR of 3.

The Need
Since there are many many high-quality, related links incoming to our website, and we are having trouble getting most people to change the links to the new website (people are busy, lazy, etc...) I'd like to find a way to pass on some of the PageRank to the new website. I still want the sites linking to us to change their links to our new URL, but realize that is just a long battle of nagging we'll have to keep up for a while to get even most of them to change.

From what I understand the 301 will help me to pass on some PageRank. Does this happen immediately on at the same pace as normal PageRank adjustments (may take a few months to see increase from many links)??? Also, can I "just" do this for the homepage - i.e. redirect URL1 to URL2 and not specify any file names? I do not want redirect any files since the whole navigation structure and everything has changed, plus there are still a couple of files on the old site that are still in use.

If I redirect URL1 to URL2 will URL1/page-name.asp still be accessable to those who click on a link directly to it? Or, will it also redirect every single file to the new URL????

Thanks ahead of time!!!