I have a Windows XP Pro box with two Gigabit RJ-45 connectors on the
motherboard. I have two separate company broadband connections at home
- a cable and a DSL that are both wired into the house with separate
jacks. How do I configure Windows to use both of these connections and
do you think that I could then use them simultaneously? Thanks in
advance.

You can if you have a dual WAN router. This search result may  help,

routing Two gateways for redundancy Understanding Route Automatic Metric We have a PIX 515. what's the command to block outside people ping public ip ...
      www.howtonetworking.com/routing.htm 


Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
  I have a Windows XP Pro box with two Gigabit RJ-45 connectors on the
  motherboard. I have two separate company broadband connections at home
  - a cable and a DSL that are both wired into the house with separate
  jacks. How do I configure Windows to use both of these connections and
  do you think that I could then use them simultaneously? Thanks in
  advance.

Looking for mail server software...
Ping does not work in both directions
Can not connect to internet
Priorities between 2 networks
How "convert" favorites folder to a list...
100MB NIC's running at 10MB
XP Pro Peer to Peer Networking Issue
Web-Browsing Problems with Netgear Router
IP Address Renewal Failure
Locking Down Desktop/Laptop Wireless Access