
Gmail… Googles answer to web-based email
"Google believes people should be able to hold onto their mail forever", the company said. That's why Gmail comes with 1,000 megabytes (one gigabyte) of free storage - more than 100 times what most other free webmail services offer."
You can check it out at http://gmail.google.com/
However it is only in its beta stages and not yet widely available.