One simple way is to find a USB memory stick and copy all the documents over at the PC end, then do the opposite on the Mac end.
For mail it depends. Is the mail only stored on your PC or on a server? If its on a server you need to configure Apple Mail or Microsoft Outlook 2011 for Mac to the same server and the mail/contacts/calendar items should just appear.
If the mail is stored only on your computer, you need to export it to a PST file and import it on Microsoft Outlook 2011 for Mac. Remember then to plan how to move forward. Will you use both computers moving forward? Depending on the service, you may need to do some reconfiguration on either end and should ask your provider for details.
Let us know if you need additional help.