First of all what game is the side for ? Sure you can print it locally but If it's artwork that exists in the community likely will be nicer and silk screened. If you get it done on your own they will probably use 3m UV blah blah blah inkjet. If that's the case I would recommend Scott at :
http://gameongrafix.com/
Again better quality artwork can be found at:
Thisoldgame.com
PhoenixArcade.com
Gamestencils.com
To name a few. The only problem is that not every game has been given the quality upgrade of being silk screened / vectorized. So if it's an obscure kit game chances are you will need to clean up your own scans or have scott / a local printer print them for you.