Mining software must communicate with a pool/proxy/bitcoind for two reasons; to get work and to submit work.
The most common protocol (supported by every mining software I've seen) for that is JSON-RPC:
http://en.wikipedia.org/wiki/JSON-RPC.
This is the request a miner makes to the server to get new work:
{"params": [], "method": "getwork", "id": "json"}
An example response by the server:
{"id":"json","error":null,"result":{"midstate":"b07ab2ccf48b89a0217384c1299d8b7e7cc9bb7ac16dd1366d9955669cb253aa","target":"ffffffffffffffffffffffffffffffffffffffffffffffffffffffff00000000","data":"0000000146f6a6158418099f9c3a68ffec435166cfdb9eef51479153000001ee000000004d3a3c9c00dc8b69df7c0e9b4f3fa4ea587cddd2392d186e9dca1b5ea1669ea74e03844d1a13218500000000000000800000000000000000000000000000000000000000000000000000000000000000000000000000000080020000","hash1":"00000000000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000010000"}}
An example of the request made by a miner to submit results:
{"params": ["000000019a086f0290f4b6d34a6e1b8a4b9974d585819abcd8e8f3d400000b5d00000000aaf9271bb6c2892dd5f96a71da1ed4be9b234f74a8de246acd91851a6639e1904e0384731a132185d1684680000000800000000000000000000000000000000000000000000000000000000000000000000000000000000080020000"], "method": "getwork", "id": "json"}
And the server's response (if the result was correct):
{"id":"json","error":null,"result":true}
Thanks. Will give it a try. 
