i want a 5-6 letter .com domain name.  how do i find out what's
physically available, even if it's a nonsense, but easily spellable
word like nelsop?  is there a website that can list all of these for
me?  i have been to register.com, joker.com, etc. but you have to plug
in each name to search it.  is there a site that lists all available
domains?

There are about 320,000,000 possible 5 or 6 letter .com domain names,
quite a bit more if you allow for the use of hyphens, and billions if
you allow for the use of numbers.  Collecting that information from an
outside source, even domain registrars, would take too much time to be
of use, so the only possible source of this information would be from
Verisign, which controls the .com domain registry.  Unfortunately,
Verisign makes no such master list of registered domains or available
domains available.  So I am afraid that it will be impossible for a
researcher to comply with your request.

The best strategy remains to think of terms or brands that relate to
your site, and keep trying until you find one that is available.

http://www.stuckdomains.com, you could search for domains names which
are going to expire or have been dropped... :)

There are times.. where you get some good names.. They give you few
options.. might help you for searching a particular name..:)

www.teddycaddy.com/catalog/

This has a great domain name search tool as well.

Visit awesome.biz, lazydomains.com, www.scriptsearch.com/details/9931.html, etc.

You will find ample 3,4, 5 and 6 letter domains on these websites.
There are other older and non-updated websites on the net that list
out all the available 3,4,5 latter domains but mostly all of these are
now taken.

You can try searching for 5 letter domains on google.com and you will
get a list of all such sites offering available 5 letter domains.