Digituna.com - websites, whois and more
I've always needed a tool which can gather every possible information about particular website, eg.: WHOIS, DNS hosts, and even opened ports on each host.
With digituna.com You can easily discover a domain's: DNS hosts (A, MX, NS), WHOIS lookup, webserver details, and more (in the future).
Right now Digituna is a convenient tool to sniff the web.