How can I convert mail system X to Exchange?

Start the Migration Wizard (Start - Programs - Microsoft Exchange - Microsoft Exchange Migration Wizard)

Select MsMail for PC Networks and click Next

Click Next to the dialog box that explains how MsMail and Exchange can coexist

Enter the Path to the MsMail post office and the Administrator account name and password for the Postoffice, then click Next

Select "One step Migration" and click Next

Select the type of information you want to import and click Next

Click "Select All" to migrate all users and click Next

Enter the name of the Exchange server to store the new accounts and messages. Click Next

You will now need to select the type of access for the shares MS Mail folders, the common one is "Author access: read, create, edit items" and click Next

Select the recipient container and template (optional), click Next

Finally choose the type of passwords to create for the new Windows NT accounts that will be created from the MS Mail mailboxes. In a multi domain environment you must select the domain for the new accounts. Click Next to begin the conversion.

A process box will be displayed showing the progress, once completed a dialog will be displayed and click OK to complete.