This is a nice informative article as it describes both manual and automated solutions in a simple way. But, I faced a limitation while using this tool that there is only single preview mode to open and read the email messages. So, I found a application named MailPro+ which offers 9 different viewing options. It also provides option to export MBOX file into 7 different formats including PST.

Users can have a look at the software: http://www.mailproplus.com/email-conversion/mbox/pst.html