K-9 Mail is an open source, lightweight mail client for Android, with GPG support.

Add an account

Tap the menu button, and tap + Add Account.

Enter your email address.

Tap NEXT and enter the password.

Incoming server settings

For What kind of account is this? tap IMAP.
Enter the following settings:
IMAP server: imap.imaginet.co.za
Security: SSL/TLS
IMAP Port: 993

Tap NEXT.