These newsgroups will only work if they are available to you through your service provider. If you click on a link and get a message like "No such group exists" or "Newsgroup not found" all you have to do is send an email to whoever supplies tech support for your isp, usually an email address like "support@ABC_ISP.COM" and ask. Most service providers are happy to add newsgroups their clients want.
Not all of the Usenet newsgroups below are strictly vegetarian but there's enough threads about fat-free or low fat cooking to satisfy. Just take what you need and leave the rest. If you see a post from "Sue in NJ," that's me. :)
