Hi Raymond,
If I understand the question right
(sorry if I did not)
You are looking for the Chicago SKYWARN frequency, and how to get it corrected on their site.
What I do is, I use the search feature on the scanner. I search 145.000 - 148.000
Most SKYWARN freq. are in that freq. range (some use different bands, but most are vhf)
If you mean their site is down, it is pretty easy to find the contact info. of a webmaster, via whois
If the Chicago SKYWARN has a site and the information is not correct on their site.
The best thing to do is find the correct information, then contact the webmaster of the site.
Usually found a contact page, or the very bottom of a site.
When you do, let them know the information is not correct, then provide them the correct info. along with the source.