If you get the following error on a WSS 3.0 site:
Access is denied. Check that the Default Content Access Account has access to this content, or add a crawl rule to crawl this content. (0x80041205)
Then check that you are not being blocked from searching due to Kerberos restrictions. The search service indexes the content of the site using the default URL for the WSS site, so if this is sts3://servername:port then all should be well, but if this is a FQDN style URL (such as sts3://www.sharepoint.site:port) then you need to either delete the site and recreate with NTLM security or add a SPN to the server.
To add an SPN use setspn from the Windows Server Support Tools. The command is:
setspn -a HOST/www.sharepoint.site SERVERNAME
Where SERVERNAME is the server running WSS and www.sharepoint.site is the default URL of the site. See alternative access mappings in Central Admin for the default URL.