A few MAC Questions...

Now this doesn't really have to do with gaming much but thought I would ask these questions to see if anyone here can give me a bit of info:

(mods if this is the incorrect location to ask these questions, please guide me to the correct place)

1) Is there a way to lock down USB ports on a MAC? (memory sticks, external HDD), but allow the keyboard/mouse of course?

2) What's the best free or paid Antivirus available for MAC?

3) Is there some kind of "web reporting" software available for MAC? As to do reports on what websites the user visited etc.

4) Pros and Cons of joining a MAC to a Windows Domain?

Thanks