Hi there,
The Bitcoin-Qt client is a good general purpose wallet, however it can take a long time for it to sync up with the blockchain (it has to download 10-12GB). The Multibit wallet is another good alternative that skips the lengthy download.
Yes, your balance should accumulate until you transfer it out to your wallet.
Here are a couple of guides that explain a bit about what you can do with Bitcoins and wallets. Pay particular attention to the part about not losing your wallet.dat.
https://bitcointalk.org/index.php?topic=321579.0https://bitcointalk.org/index.php?topic=17240.0Namecoins are similar in that they are another cryptocurrency, but they also functions as an alternative P2P DNS system.
Cheers.