Does it hurt or help if you have a sitemap for www and @. Google indexes domains both ways and I was wondering if it would help to have 2 sitemaps, one for each record. www - www.example.com @ - example.com
Since Google sees these as two different domains and each of them would contain identical content, I'd suggest picking one version or the other and sticking with it. I have always found that concentrating your link value on one version (one well-ranked site) is better than having two half-fast sites going (two that aren't ranking real well).