You can get better pings by locating your server closer to your users and choosing optimized bandwidth. You can purchase servers in different locations and allow your users to choose one that's closest to them. Optimized bandwidth, like Internap, can lower your ping times. Quality bandwidth will be more expensive, so unlimited bandwidth is rarely an option.
Once you have found a good network, the host should be able to accommodate you with the actual server hardware.
I'll let other more knowledgeable people provide you with information as to where you can find the server that meets your needs. But I just wanted to let you know that there is no such thing as "lag free". If you have a server in the East Coast of the US, someone with a dial up connection in the West Coast is going to lag. You can't provide a lag free connection from a single machine to the entire world. Just FYI. I pass this knowledge on to thee, now go forth and conquer.
thank you very much,
#lchan, you are totally right, but I'm from Asia, to be exact, Saudi Arabia ( and most of my planed customers are )
so the closest location would probably be like ... UK and Germany and Maybe US
so it really doesn't matter, the ping rang is about 100 - 200
But its all about the server performance, and would it be able to hold that amount of players at the same time without crashing or LAGGING or disconnecting players ...etc