Kevin,
welcome to the DotNetNuke community, one of the strongest community at least at DotNet projects - IMHO one of the major advantages of DotNetNuke. Another advantage is a qualified, stable developement team, that stands for high quality, secure code.
Reegarding your questions:
KingDesign wrote
1. Do I have to know any programming (i.e. VB.net, C#) to make this work?
No, only if you want to create your own module or core tweaks.
KingDesign wrote
2. I notice that the speed of mambo is a bit faster (noticeable) than dotnetnuke, is this an issue that is being addressed?
There is a speed up time for compilation, that is determined by the platform ASP.Net. ASP.Net 2.0 speeds up, especially when the project is pre-compiled; AFAIK the core team is looking, how to archieve this.
KingDesign wrote
3. What standard modules come with the default install of dotnetnuke?
The core comes with a couple of basic modules, the list can be found here: http://www.dotnetnuke.com/tabid/179/Default.aspx
KingDesign wrote
4. I see the list of module projects that are currently being worked, do these ALL have to be individually installed after the initial dotnetnuke install?
All additional modules can be installed (and updated) individually.
KingDesign wrote
5. Do I have to know VB.Net to install the modules or make small modifications?
There is a built in installer, where you can either place all modules into a special directory on the server (e.g. via FTP), so they get installed automatically, or you can upload them interactively from the menu (log in as host, select menu item, choose module package from your local drive, do two additional clicks and it gets installed automatically. Same with Skins and language packs.
KingDesign wrote
6. Is there a DEMO website somewhere to login and "play" around with?
(Mambo has one 
There are some around, please look around in these forums. (My company has one for our German customers, that might not be appropriate).
KingDesign wrote
7. Concerning the design/look of the website and Skins: Are skins easily editable for someone who has expert knowledge of HTML-CSS-DHTML?
Editing a skin means creating an HTML page with a few specific tokens, add css and an (optional) xml file with additional attributes. zip all files and upload the zip, so it gets compiled.
Hope I could help you a bit.