I have a portfollio of domain names that I would like to sell.  I
would like a list of companies or websites that list names for sell or
would act as a broker.  Included I would like to know who is the
bigest seller or in your opinion who would be the best value or the
more likely to sell the website. Thank you

I have had some experience in this and have had mixed results.  Like
any goods that you are selling it is the quality that counts, if you
have a 3-letter domain name you will have no problem selling it.  If
you have a known brand name or common english name you should also
have no problem selling it.  If the domain name is more obscure,
contains hyphens or is mis-spelt you may run into more difficulties.

My first advice would be to build a webpage at the domain name that
you wish to sell stating that the page is for sale.  Putting a price
on this page is more likely to produce results than simply just
stating that the domain is for sale and please contact the user.  I
have managed to successully sell a few domains this way and it is free
and all the profit goes into your pocket!  THIS IS A "MUST DO"!

The next cheapest option I would try would be eBay.com (note: sell a
.co.uk at ebay.co.uk, a .com and ebay.com etc).  The fees at eBay will
depend on how much the domain sells for.  You should also follow all
the usual eBay advice when selling your domain such as get your money
first before transferring the domain over to the buyer and price the
domain name sensibly (a lower starting price is more likely to get
bids than a highly priced item).  It also helps here if you have a
good eBay selling reputation although this isn't necessary.

You may also find online forums such as http://www.dnforum.com/ useful
in your quest to sell your domains (I have never tried this option but
it looks like at least a good way of advertising the domain is for
sale!).

My final option would be to use one of the following brokers:

http://www.afternic.com/
http://www.greatdomains.com/
http://www.domainrace.com
http://www.hitdomains.com
http://www.sedo.us/main.php3?language=us
http://www.names123.com
http://www.urlmerchant.com
http://www.thedomainexchange.com/
http://www.urlcollection.com/
http://www.domainmart.com/welcome/FAQ-Sell.htm
http://www.hostcompanies.com/selldomainnames.htm

I have had NO SUCCESS in selling any domain names through this process
even though I have tried several times.  These companies have varying
pricing structures so it is best to read the small print carefully. 
Some allow you to list the domain name for free and you only pay them
if the name sells, others require a fee to list the domain name. 
Personally I would go with one of the companies towards the top of the
list who have been in the business longer and are more well known.  If
I had to use this option again I would use Afternic who were the most
helpful to me and appeared to have the largest choice on offer for
customers.

You may also want to contact the people you registered the domain name
with, they often have a service to sell on the domain name to other
customers for free.

To conclude my preferred option to sell a domain name is a page at the
domain in question coupled with an eBay auction.  You may also like to
contact a few companies or individuals who may have a use for the
domain name (although spamming them would  be a bad idea!).

Finally for other opinions on selling your domains you may find this page useful:
http://www.domainguru.com/c/50

As a useful guide and something to dream about remember these sales:

Business.com	US$8 million 
AsSeenOnTv.com	US$5.1 million 
Altavista.com	US$3.3 million 
Wine.com	US$2.9 million
Autos.com	US$2.2 million
Express.com	US$1.8 million
Wallstreet.com	US$1m
Rock.com	US$1m
Websites.com	US$970,000
Drugs.com	US$830,000

Good luck with your portfolio!

perfect,  thank you so much

just a comment. Unless the domain name is a common popular everyday
word like, "cheese.com" or "woman.com", they are difficult to sell. I
think your best bet would probably be on ebay. Good luck!

I like greatdomains.com.

http://www.greatdomains.com/