I have a collection of .info domain names some of which I wish to
attempt to sell. Most fall into groups for example  europetourist.info
and europevisitor.info coupled with several dozen xxxxxxtourist.
xxxxxxvisitor.info   the xxx being the country name capital city or
tourist region.  Other groups relate to sport such as golf,
rugby,cricket. Are there any web based organizations where these can
be marketed or possibly auctioned?

There are lots of web sites where you can market/sell your domain
name.  Each has different fees and commissions associated with it. 
Therefore, you will want to look at several of them before selecting
where you want to list your domain names.

"Afternic"  www.afternic.com

"GreatDomains" www.greatdomains.com

"Domain Barn" www.domainbarn.com

"Sedo" www.sedo.us/main.php3?language=us

"The Domain Name Aftermarket" https://www.tdnam.com/trpHome.aspx?isc=goodna303a

"Website Trader" http://www.websitetrader.com/

These are brokers, who typically charge a commission based on the
selling price.  Some also require fairly modest annual fees to list
your domains.  Some offer appraisal services of various kinds.

While I cannot guarantee its objectivity, here is some information
that may be useful to you in choosing a provider:

"Service Providers" AboutDomains.com (2005)
http://www.aboutdomains.com/ServiceProviders/brokers_list.htm

"Domain Name Brokers" Internet Gold Rush (2005) http://www.igoldrush.com/links3.htm

Here is an article recommending how to sell domain names:

"Cashing in on Unused Domain Names" WebReference Update Newsletter
(August 4, 2000) http://webreference.com/new/domaincash.html

Sincerely,

Wonko

Search terms: "domain name" sell

Try this out.

http://www.nameslot.com

Try http://www.nameslot.com for buying selling and talking abut domain names.