FastMail.fm
Someone on an online community posted a request for free Webmail that allowed IMAP access and someone replied with FastMail.fm. I signed up for an account and I must say it's pretty damn cool. Their web interface is quite decent, their site is fast, and yes they offer both SMTP and IMAP access for free! You get 10 megs of storage, and 40 megs of bandwidth a month for free, but that should be enough to do some simple emailing. For a one time fee of $15 you upgrade to get more bandwidth and more storage even. Not too shabby!