Comment Private Zimbra installation (Score 1) 385
While it's totally overkill for the job, I highly recommend you run a Zimbra Open Source instance for yourself. Although you don't need much of what it provides (Calendaring, contact sync, Jabber IM, etc), it will let you store your messages in a stable, searchable and accessible form. Zimbra can directly import from PST or via IMAP (with your mail client or imapsync) and once it has your messages it full text indexes them with Lucene and so you can search them via the web or IMAP clients. You can easily get your messages out via one of the supported export formats or just use your IMAP mail client to dump the messages into mbox/maildir/pst/whatever. While you could certainly roll your own, why not let someone else take care of all the hard work for you?