W3C - The World Wide Web Consortium (W3C) develops interoperable technologies (specifications, guidelines, software, and tools) to lead the Web to its full potential. W3C is a forum for information, commerce, communication, and collective understanding.
Introduction to HTML - A good tutorial on HTML located at the University of Toronto.
CGI Made Really Easy - This primer focuses on writing CGI scripts to process HTML forms on the Web. It skips some details, but can bring you up to speed fast (literally an hour or less), and covers 90% of real-world situations.
CGI Resources - An index of CGI resources.
Google Datacenters - McDar's famous tool for checking different datacenters at Google. Not as useful as it was in the old "dance" days, but it still comes in handy.
SEO Guy Forum - A great and friendly forum devoted to discussion of search engine optimization (SEO).
A List Apart - A useful online magazine with articles related to web design and development.
Inner Peace - The Inner Peace Webmaster Toolkit. Lots of small but useful tools to help webmasters.
IP 2 Location - The best way to convert an ip address to an actual computer or company. Allows up to 20 lookups a day for free.
Network Tools - Many useful tools for looking up domains and ip addresses. Also useful when you have trouble connecting to a site.
Reverse DNS - Another useful reverse DNS utility. This site often gives information when ip2location is not specific enough (and vice- versa) so it's ofen useful to check both if you really care to know who a particular ip address is.
Network Solutions - This site is particularly useful for its whois lookup script. You should note that I don't list it as a option for registering domain names because their prices are much higher than other companies.
GoDaddy - The place where you should go to register domain names. There really is no other option.
Misk - Another option for registering domain names. I used them for a while (when they were registersite.com), and they were good to me. At the time I needed their "cloaking" option, but once I no longer needed that option I ended up transferring my domains to GoDaddy.
ZoneEdit - A very good option for DNS services if your host doesn't provide DNS. I am currently using ZoneEdit for one site that I manage because I have no other way to link the domain name to the actual site. They offer both free and paid services, depending upon your needs.
Public DNS Service - I haven't had the courage to give this a try, but they offer complete DNS service for free.
1 and 1 - The professional hosting company I use for all of my web site hosting needs. They offer many different packages.
Admin.1and1 - The administration control panel for 1and1 hosting. Not useful unless you have a 1and1 account.
Forum.1and1 - A very useful forum for webmasters with sites hosted on 1and1. Again, not very useful if 1and1 is not your hosting company.