SendMail + WebMail

I am wondering any one has configured any web mail program. Could you recommand the easest Web mail program? I am using R.H.7.2 and I have sendmail installed. There is no POP3 account yet but I will have soon. Since I have some time, I would like to figure web mail out and let my client check mail trough web browser from their PC. Any sugguestion or recommandation would be apprecitated.

Sunny,