What open source miner applications are there? What open source miner applications are there? Especially to see how the mining process works.
The official list is on The Wiki and is constantly being modified since new software shows up fairly often, but here's the quick breakdown:


Poclbm - Python/OpenCL GPU miner (GUI)
DiabloMiner - Java/OpenCL GPU miner (MAC OS X GUI)
RPC Miner - remote RPC miner (MAC OS X GUI)
Phoenix miner - miner
Cpu Miner - miner
Ufasoft miner - miner
Pyminer - Python miner, reference implementation
Remote miner - mining pool software
Open Source FGPA Bitcoin Miner - a miner that makes use of an FPGA Board


Poclbm and Phoenix are probably the most popular (links go to the sources) though that's based more on my opinion than any facts or studies. In either case, both should shed some light on the mining process.