I am building a website which requires the use of cookies to identify
repeat users. It will be upfront and consistent with the purpose of
the visitor who will have the option to not accept it. Question: How
is a cookie attachment software introduced by a website and is there
commercial software for installing it into the website design or
attaching to the website?

http://webmonkey.wired.com/webmonkey/98/29/index1a_page7.html This
site will walk you through impementing cookies via java script, you
could also use other methods, to get a good answer from the google
pros, they will need more info, how are you coding the site? Do you
want your cookies to expire? etc.. My advice read the article then
post more info here if you still need help.

As to the usage of cookies, unless you need sessions to be persistant
upon closing/reopening the browser, I'd recommend using server based
'sessions' in leiu of cookies, as cookies can be turned on/off in the
browser, however sessions are stored server side and are persistant
within that individual browsing 'session'. To use sessions though, you
must use a serverside scripting language. If you decide to use
sessions instead of cookies, let me know what scripting language you
use (ie PHP, ASP, Perl, etc) and I can work up a simple example for
you.

I would use sessions and cookies. rember alot of people disallow
cookies on their computers becuase of security risks. but u should n
ot use java script as a programming language u should use dynamic
languages such as cfm, asp, php, or c++(cgi). u good example of how to
use both is using a file or a database to store a MD5 string with all
the info u would store in a cookie. then palce the cookie with that
md5 string for it to check the DB for once they open the page again.
sessions only last aslong as that browser window is open.