Learning from a source code is very useful at times, but it is a pain if the code is not commented well. Which of the open source Bitcoin software have the most thoroughly and understandably commented source code? That is, if someone wanted to understand how the main client, miner, pool or other Bitcoin software works, which projects should one look at?
I remembered that I had seen answer to that question somewhere, after searching a bit I found it here.
Check out BitCoinJ (a from scratch bitcoin implementation in Java) and BitCoinSharp (a C# port of BitCoinJ). They are not full implementations yet, but they are very far along and can do most of the tasks of a bitcoin client.
No matter what language you plan to create your implementation in, looking at these is very valuable because they are very thoroughly commented and much easier to understand than the official C++ client.
weird, because it's the answer to your other question.