Maintenance at 50,000 miles

Hi All,
 
I purchased Mazda Protege 2003 with 48500 miles on it. Somebody suggested me that I should get a maintenance service done. Can somebody tell me what all should I be looking for here?
Also, I can here the engine noise at a higher pitch then normal, is it regular with Mazda protege? Or could there be something wrong?
 
Thanks
Ankit

How long have you had it and what maintainance have you had done so far?  Has it been tuned recently?  Besides what seems to be higher than normal engine noise; how does the car perform?