Now that most of the fun of SQL Slammer has died down, let me present you a tool that might have prevented it: Update Expert.
Basically what it does is query all the NT/2K/XP machines on your network, then query its own database, and tell you what Microsoft patches are available to you. Then it’ll help you download them and push them out. It even figures out the order to install the patches (important) and knows which ones can be installed together to minimize the number of reboots. It’s a lot better than running Windows Update on every PC on your LAN.

I have no connection with St. Bernard Software. My former boss used it and swore by it; when I changed jobs, I introduced it to my new boss. I recommend it because I use it myself.