[Sigon]

1. I don't know of any templates but SaintDog has a site www.bbaddons.com that you can get a few cool looking styles to use if you want.

2. Assuming you are changing everything or the essential things. It really depends on how much you are changing. Like my site here: www.blizzardforums.com I changed the logo, buttons and also the Forum, Posts, Threads, Moderator bar and replaced it with images and such. I also edited the footer and main forum sections. Took me a few hours. Here is a tip/hint for you. Before you start your editing create the site the way you want it to look in your fav image design program. Then slice it up and you are all set from there. Take a tour through your templates and get to know them. If you plan on using Vb for a long time they will become your best friend.

3. Once you have done your first total change-over and you get the hang of how things are run you should be all set and ready to go. The second, thrid, fourth, etc times you change shouldn't be that hard for you to do. I just do reccomend something. When you have a good design going keep it till you get bored or you think your members will appreciate something great. If you keep changing things daily your members might get a little upset that they just got used to one design now they need to get used to another.
Anyways. Good luck and have fun! Cause that is really what it is all about.