While unsupported, iCloud still allows access to your e-mail via IMAP, and sending via SMTP. Apple has published the necessary parameters for manually configuring your e-mail client to use the iCloud service.

Incoming (IMAP)

• Server name: imap.mail.me.com
• SSL required: yes
• Port: 993 (is set by default)
• Username: example@me.com (use your @me.com address from your iCloud account)
• Password: Your iCloud password

Outgoing (SMTP)

• Server name: smtp.mail.me.com
• SSL required: yes
• Port: 587
• SMTP authentication required: Yes
• Username: example@me.com (use your @me.com address from your iCloud account)
• Password: Your iCloud password

SSL is required for both IMAP and SMTP. POP3 is not supported.

Source: http://support.apple.com/kb/HT4864