If you want to make real mining pool service, there are open source pool software named pushpool.
You need quite high skill of Linux and server programming.
1. Make Linux server with ubuntu installed
2.download and install bitcoind from official site
3.download and compile open source pool mining software pushpool (require mysql)
There are technical support here.https://bitcointalk.org/index.php?topic=10321.0
4.setup database, bitcoind to run as deamon server, pushpool to connecting with bitcoind
5.register pool workers in pushpool's mysql database.
6.connect to pushpool's rpc interface with bitcoin mining software.
There are all information in this forum to create mining pool and every source code(completely free).