Wow. I REALLY didn't think that anyone but me would be interested. Yet, in less than a month after posting, I get a reponse. Very cool. About your questions, I'll give you short answers for now, but feel free to email me for more in depth responses. Lots of other people have had similar questions in other forums, it seems that codeweavers should put together a web page or something (beyond the very brief description given when you're about to sign up). Here's the gist of it:
As an advocate, you contribute to this Dentrix app entry that we're in right now. Notice the tabs above (screenshots, forum, known issues etc) Being an advocate allows you to edit all that. So, you're supposed to dump all you know about the app this entry. Also, you should subscribe to a mailing list (http://crossover.codeweavers.com/mailman/listinfo/discuss) so you can help answer questions. You should periodically test the beta/nightly builds of the product with Dentrix to see if any problems come up. Hmmm...I'm making this look really complicated, but it's really not. The main idea is just to try to help get Dentrix to run in whatever way you can. If you can't program, fine, just test. If you can tweak something to get it to work better, let everyone else know. You'll see on the Dentrix website that they offer a free demo. You could start with that. I, personally, would consider it totally ethical to copy a Dentrix install CD from a dental office (with permission) if it is for the sole purpose of testing compatability. I'm sure Dentrix would have no problem with it either, since we are helping them get their app to run, which is really their job. So consider that way of getting hold of a copy for testing too.
Ok, so if I haven't scared you off yet, I highly, strongly suggest that you become an advocate. It will really show that there are people interested in this app. And don't worry, there is no 'advocate police' or anything. Just do the best for your ability, and no one's gonna care. I've worked with some of the guys at CX and they're quite relaxed and very helpful.
It's also a good idea to email Dentrix to let them know that there is demand for a Linux port. I've gotten the impression that they are going towards .NET for future releases, which might be the way they plan to achieve portability.
I've been toying with the idea of opening a small startup co. that specializes in helping dental offices make the transition to Linux. Once Dentrix is stable on COO, this kind of thing would really attractive to the dental community (at least my experience has shown so). Plus, one could offer Open Dental as an open-source alternative to Dentrix and REALLY provide a great alternative.
My email address is danny at amelang.net
Danny