I don't find anything on readers for .pst files, but OL2002: How to Work with Personal Folders Files may be of some help. It does indicate that you can, from within Outlook, copy .pst files/folders elsewhere on the drive for storage, and can open them in Outlook from any location.(?)

A "glitch" perhaps worth noting is I've seen several articles that say that (for OL2002 and later at least) you cannot import .pst (and some other) files directly to Outlook from a CD backup. Outlook cannot open files with "Read Only" attribute set and files on a CD are inherently read only. You have to copy to your hard drive and remove the read only attribute before you can read them in Outlook.

John