I have a client that is looking for a way to archive their email (making it searchable, etc) -- all on a shared hosting account.

I was kind of thinking of having some way to parse/store email in a MySQL database and make it searchable using a PHP application. But I'm not sure how to parse the headers (if it's even possible to do so).

Any other ideas on this type of application? They are wanting a way to archive email, make it searchable, keep a record of all emails sent, etc. They're willing to "purchase" a mail server if necessary. But I'm hoping to find a way that they won't have to.

You can take a look at xapian. Depending on how you index the mail, you'd be able to do searches such as:You'll also have to think about how to archive the mail, e.g. the search can return a list of IMAP UIDs underneath, or whatever.