Emailchemy has been my tool of choice for a loong time for converting email from many different formats/clients
From their site:
Convert: Emailchemy converts email from the closed, proprietary file formats of the most popular (and many of yesterday's forgotten) email applications to standard, portable formats that any application can use. These standard formats are ideal for long term archival, database entry, or forensic analysis and eDiscovery.
Migrate: Emailchemy includes an embedded IMAP mail server from which any IMAP-compatible email application can import your converted email. Emailchemy also includes a utility for uploading converted mail up to a Google Apps email account.
Manage: Emailchemy provides utilities for splitting, sorting and merging email archives, and harvesting email addresses from email archives.
- Convert proprietary email formats to standard formats based on RFC-2822 (formerly RFC-822) -- the official Internet standard for email messages that has been around since 1973.
- Cross-platform solution; versions for Windows, Mac, and Linux
- Reads native email file formats;
- no need to re-install or run old email programs
- convert Windows email files on a Mac or Linux computer, and vice-versa
- Convert all your old mail formats with a single product
- Industrial-strength accuracy relied upon by law enforcement and forensic agencies around the world
- Embedded IMAP mail server to simplify importing email into most email client software.
- Upload converted email to Google Apps email accounts.
Supported Email Formats
Emailchemy can read most email file formats and convert them to open standard formats. Emailchemy can also host converted mail on an embedded mail server, providing a universal method for importing email into any IMAP compatible email application.
Emailchemy can read:
- AOL for Windows ("PFC" files)
- Claris Emailer for Macintosh
- CompuServe Classic for Macintosh (aka "MacCIM")
- CompuServe 2000 for Windows
- Entourage (Database, .RGE Archives and cache files)
- Mac OS X Mail
- Outlook for Windows (.PST and .OST files)
- Outlook Express for Macintosh
- Outlook Express for Windows
- Outlook Express for UNIX/Solaris
- PowerTalk/AOCE for Macintosh
- QuickMail Pro for Macintosh
- QuickMail Pro for Windows
- Yahoo! Mail
- any UNIX-style or mbox-format mailbox
Emailchemy can write:
- RFC-2822 mailboxes ("mbox" format, mail spool, or "UNIX-style")
- Folders of .txt or .eml files (RFC-2822 message files)
- Comma-separated value files (.csv files)
- IMAPdir (Binc IMAP maildir)
- Maildir++ (Courier IMAP maildir)
- IMAP email account and folders usable by
o Outlook Express
o Mac OS X Mail
- Variations of the RFC-2822 mbox mailboxes that are directly usable by:
o Mac OS X Mail ("Mail.app")
o Entourage (.rge archives)
Emailchemy runs on:
- Mac OS X versions 10.4 or higher
- Windows with Sun Java 1.5 or higher (32-bit version)
- Linux, Solaris, or UNIX with Sun Java 1.5 or higher
- Minimum 1GB system memory (RAM) recommended
- Get the latest version of Java