NTFS-3G to the rescue
I have a really old PC that I used from about 1998 until early 2001. I think it has a Pentium 233MMX processor. Its hard drive contains all of my email from about 1995 until early 2001. Back then I used PMMail, first on OS/2, then on NT4 and W2K.
I tried booting up that computer last night, but alas she won't go. I took out the drives and plugged them into a USB2 enclosure. The 6GB drive (yes, 6GB, not 6 billion bytes) wasn't readable, I'll plug that into a Linux box to figure out exactly what types of partitions are on it, but the 20GB drive has several NTFS partitions on it. I used NTFS-3G for MacFUSE to mount it on my Mac.
I'm going to try to convert my PMMail mailboxes into a format Mail.app can import. Thankfully, PMMail stored each mail message in its own file in plain text, so this won't be hard.
Also found on those drives are many software projects from the 90s including dynAuthor, a threaded chat client for Frontier, a Frontier suite for generating and controlling Windows GUIs, and more. Lots of WebObjects and ASP code too. :-)