It looks like you have two questions here:
I'm trying to setup the Windows 2003
server (a domain controller) to have
VPN with NAT. Having a heck of a time
getting it setup
I commented on your question with questions of my own. I might be able to help if you can elaborate a bit. Either way, you'll have to forward VPN ports on your wireless router to your DC so your DC can handle the VPN traffic.
The cable modem is connected to a
Wireless router which works fine for
wireless devices. But I'm having
trouble with users logged into the
domain. They can access the domain but
not the internet. I'm sure i'm missing
something simple. If anyone has any
ideas I'm open.
You may want to ditch DHCP on the wireless router and use the Windows DHCP Server. It's a bit more robust than your average wireless router (though, I don't know what you have so that may or may not be true). Either way, there are two things you may be missing that is preventing users on the domain from accessing the internet: a default gateway, and dns servers.
In your DHCP server, make sure you are passing out a default gateway with the address of your wireless router, and also the address of whatever is serving DNS for you. If it's your domain controller, then hand out that address. If it's your wireless router, then hand that address instead.
You can check what these values are on your desktops by doing an ipconfig /all command from the command line. If you are missing one or either, or they are pointed to the wrong place, the "internet" won't work as expected. Look for Default Gateway and DNS Servers ip addresses. It should look something like this (this is a Windows 7 snapshot on my LAN):
Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . : irdev.local
Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
Physical Address. . . . . . . . . : 00-22-68-46-46-85
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::e0fe:f05a:ea7d:bb17%10(Preferred)
IPv4 Address. . . . . . . . . . . : 10.0.10.0(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Lease Obtained. . . . . . . . . . : Wednesday, June 29, 2011 12:36:39 PM
Lease Expires . . . . . . . . . . : Thursday, July 07, 2011 12:36:37 PM
Default Gateway . . . . . . . . . : 10.0.0.2
DHCP Server . . . . . . . . . . . : 10.0.1.1
DHCPv6 IAID . . . . . . . . . . . : 234889832
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-13-6D-44-E8-00-22-68-46-46-85
DNS Servers . . . . . . . . . . . : 10.0.1.1
10.0.1.2
NetBIOS over Tcpip. . . . . . . . : Enabled