1 ? - Should I give all my client Pc's different Ip's or is that not really necessary?
If you setup a domain with a DHCP/DNS server running then it isn't really neccesary but if talking about a smaller (under 100 systems) I would still recommend it for reporting/accountability.

2 ? - How would I go about locking client's terminals such as their control panel games and such, so that they are only allowed to look at what I want them to?
SirDice had it right - setup restricted users and use policy editor.

3 ? - How can I make every computer log on to the network using different usernames and passwords without having to install all the names and password on each individual computer but still be able to access the network by using any username/password on any machine in the network?
Again like SirDice said setup a domain. I'd suggest you setup your 2000adv server that is NOT running your database application as the primary domain controller so that it continues to be your primary place to setup users/passwords etc...

4 ? - What is a good reporting tool/program or software firewall for an internal network.
- Intellimax makes some good network reporting tools, TrafficMax or LanTrend for example offer alot of good stuff. (These are just a couple of the choices, I'm sure people here can suggest many others)

- As far as software firewalls, ZoneAlarm makes a pretty good one also Sysgate does - both of which work well as a software solulotion (There are many others as I'm sure some people here can tell you of)

- And like SirDice suggested, I'd definiatly add a virus scanner solution. Both Symantec and PandaSoftware offer good enterprise solutions


Anyway, theres my 2 cents...

RRP