I've recently changed the DNS server setting on my WiFi router from the DNS servers run by my ISP with those from OpenDNS. OpenDNS runs large DNS caches which can speed up your address lookups. They also compare all URLs submitted with a phishing site blacklist to help keep you from falling prey to phishing schemes. They also correct common typing errors in URLs. For example if you type "google.ocm", they will change it to "google.com" to prevent a lookup error.
On a related note, you may notice occasionally that address loopups for an URL you've typed into your browser may fail. This can be a sign that the DNS cache on your local PC has a stale entry. Here's a site which shows how to flush your DNS cache. They've got procedures for flushing the DNS caches on Windows, Linux, and Mac computers.