PstExporter opens each pst file, scans its contents and generates a hierarchy of mbox files that replicates the structured found in the pst file. Importing these mbox files with Apple Mail migration assistant is very easy. You just select the root folder of your exported files and Apple Mail will do the rest.

Apple Mail
Messages generated by PstExporter can be imported automatically with Apple Mail.

Microsoft Entourage 2008
Entourage can import all messages created with PstExporter, but one folder at a time.

Mozilla Thunderbird and Others
Other programs like Mozilla Thunderbird, cannot read PstExporter files directly, however they can migrate all messages if they are first imported into Apple Mail.

With PstExporter you can migrate your emails from Microsoft Outlook pst files. For some users this is just fine, but many people have pst files that are updated constantly. Having to go through the export/import procedure every time the pst files are modified could become tedious. For them, we developed PST Bridge, a much more versatile application that can display pst file contents immediately without conversion. It also contains an export wizard that performs the same tasks PstExporter does.

Read more on PST Bridge here.