I used to use IC24 when it was completely free of any charges (subscription or call charges) between 8pm to midnight, seven days a week. I never used their e-mail, as Adept says it is better to have your own domain.
A really useful Pop3 service can be found through Yahoo. Sign up for a webmail account through the UK site (yahoo.co.uk) and look for the link for pop3 access. You are expected to sign up for Yahoo UK's sponsor's newsletters, but all you need to do is remove ALL ticks from the boxes, hit the button, and you have a pop3 account that stays with you. I use mine all the time, for non friends and family.
Cheers.