webmail software
 

Does anyone know a good program or a cheap service so I can offer visitors of my website free email like hotmail?

for the most part you are going to have to build your own custom scripts for this.

the free ones are so shitty its amazing, and most of the pay 1s are out of date, use there own add support in your emails, or just dont work.

also, stay away from anything that says CGI. all cgi invoked mail is being blocked by all the major isps due to spammers taking advantage. none of your members emails would get into aol, yahoo or hotmail.

Haven't installed this, but I will check it very soon:
http://www.horde.org/imp/

if you are running qmail, there is squirrelmail.

you can run twig

Try slmail its stable and has a good web based interface.

http://www.seattlelab.com/