Find exactly the domain you'd like to register, whatever it turns out to be
There are many tools available online that will assist in performing whois queries for you to determine if your favorite domain name is still available, and if not, who has registered it. These tools are usually web based and allow you to submit a few queries at a time (and frequently suggest several inane alternatives if your first choice is taken).
If you're not so much interested in a particular name as in finding one that matches a pattern, why not let the command line do the work for you? Suppose you wanted to find a list of all words that end in the letters "st":
cat /usr/share/dict/words | grep 'st$' | sed 's/st$/.st/' | \ while read i; do \ (whois $i | grep -q '^No entries found') && echo $i; sleep 60; \ done | tee list_of_st_domains.txt
This will obligingly supply you with a visual running tab of all available words that haven't yet been registered to el Republica Democratica de Sào Tomé e Príncipe (the domain registrar for the st TLD). This example searches the system dictionary and tries to find the whois record for each matching word, one at a time, every 60 seconds. It saves any nonexistent records to a file called list_of_st_domains.txt, and shows you its progress as it runs. Replace that st with any two letter TLD (like us or to) to brute force the namespace of any TLD you like.
Some feel that the domain name land grab is almost turning the Internet into a corporate ghetto, but I don't subscribe to that idea. I actually find the whole situation quite humorous.