Is it possible to access local email files reading subjects, addresses, etc?

Yes, it is possible, but you cannot automate Outlook Express. The easiest way to read e-mail in Outlook express is to use MAPI - and there are several MAPI classes available in the downloads section here. Or, if you have a copy of MegaFox: 1002 Things You Wanted to Know About Extending VFP, there is a MAPI wrapper class along with a sample form that uses it to read e-mail and send e-mail in Chapter 4:

How do I use MAPI?

To send, or receive, e-mail using MAPI, you need to instantiate two objects that are found in MSMAPI32.ocx. The MAPISession object is responsible for managing the mail session and the MAPIMessages object is used to send and receive messages. The properties, events and methods of these two objects are quite well documented in the MAPI98.chm help file. If you really need some out of the ordinary implementation, you could probably get the necessary information by studying the help file. Fortunately, for basic e-mail, you don’t have to bother.

We have created a container class called cntMapi that that hides the complexity and makes it easy to send and receive e-mail. This class was created in the visual class designer so that it can be dropped on to a form. The class could just as easily have been built as a program file, but then would have to be instantiated explicitly in code using either CREATEOBJECT() or ADDOBJECT().