Right, this is all rather intriguing but I'm rather perplexed by the lack of a username/password login thingy when I launch the client, seems all I get is a "main" bitcoin address and a receiving address, which seem to be identical. I just don't get how people can't just use my address to not just send money to it but also pretend to be me? I just don't understand it how the whole thing works.
Second question- I've had my client open for 5-6 hours or so and haven't received any money. Seems
By now, mining requires powerful GPU's to be productive. The days when mining on your PC CPU are no more.
Money does not appear from nowhere, but you can get free bitcoins donated by the community in order to promote the system from this website:
freebitcoins.appspot.com
Your ownership of bitcoin on your computer is not defined by any username/password, but rather by your possession of a small file called wallet.dat on your computer. However you can use online services to hold your money for you, and they would require a username/password to log in, for instance mybitcoin.com
If you can sell something for bitcoin, you should do so. Perhaps on biddingpond.com