How to make a Python script run like a service or daemon in Linux

I have written a Python script that checks a certain e-mail address and passes new e-mails to an external program. How can I get this script to execute 24/7, such as turning it into daemon or service in Linux. Would I also need a loop that never ends in the program, or can it be done by just having the code re executed multiple times?

Getting MAC Address

I need a cross platform method of determining the MAC address of a computer at run time. For windows the ‘wmi’ module can be used and the only method under Linux I could find was to run ifconfig and run a regex across its output. I don’t like using a package that only works on one OS, and parsing the output of another program doesn’t seem very elegant not to mention error prone.