Thanks aliashraf, can you elaborate a little about #3 please. In which case Bitcoin client (I assume wallet) have to deal with the block? Is it a special api something like audit?
And how is it possible to work with tree which is not in-memory?

Hi, here are my questions:
1. Does Bitcoin use Merkle tree for data verification?
2. If answer to #1 is "yes" - if Bitcoin keeps Merkle tree in-memory?
3. If answer to #1 is "no", than what for Merkle tree is used for? 

Hi, how the wallet knows IP & port of available node?

I got it. Thank you all very much!!!

Great ranochigo!
1. What happens if two miners create identical blocks at the same time and half of the network accept the block from the first miner and other half from the second one? Which miner will be rewarded?
2. Miners are self rewarding? Am I understand correctly? Who control them?

Thanks NotATether. Here is what I'm trying to figure out: mined block gets broadcasted to many nodes. 1. Which of those nodes make decision if block is a winner? 2. Which of those nodes initiate transaction of fees and rewards to winner miner?

Hi, does anybody know, in Bitcoin system, which process(es) managing miners payments (fees & rewards)? If you can point to the place in the source code? Thank you.