Yeah d3c0n808 is correct!
You must download, config bitcoind (Which can be found on bitcoin.org)
Then you must download, install Pushpool (for managing miners/connections)
If you want a front end you can pick one of the follow that d3c0n808 stated but naturally I'd recommend Mining Farm scince it's made by me. Anyways I have published a bunch of resources for doing this kind of things that can be found in my sig but here are the resource links:
Pushpool - Download, Installing, configure instructions for Ubuntu systems: http://forum.bitcoin.org/index.php?topic=10321.0
Mining Farm - Download, Installing, configure instructions for any self-managed VPS: http://forum.bitcoin.org/index.php?topic=10617.0
bitcoin is the easy part so there really isn't a install instructions for it.
If you have any troubles you can PM me fore help and throw me a couple of bitcoins my when upon completion of the job
I only install on Ubuntu servers