What is the standard protocol for pools/miners?
When there were no pools, all of the first mining clients interfaced directly with Bitcoin. They connected to Bitcoin's JSON-RPC interface and used the getwork RPC method to get the required work. Getting work from a pool is the same as getting work from Bitcoin. The client connects to the pool over HTTP, often using the same HTTP authentication that Bitcoin's JSON-RPC interface uses; the client sends a JSON-RPC getwork message; and the pool sends back a JSON-RPC getwork response.

Many pools nowadays support some extensions to the getwork protocol that Bitcoin does not.

See:
https://en.bitcoin.it/wiki/Getwork