If anyone does go ahead and download bitcoin (being as its entirely free I don't see why you wouldn't) make sure if you intend to use it properly you get it all together and make a nice secure package
https://en.bitcoin.it/wiki/Securing_your_walletAll I did was make a truecrypt file then mount it up as the Z:\ drive, move the bitcoin .exe and data directory to the Z:\ drive, then create a shortcut to the .exe with Z:\bitcoin.exe -datadir=Z:\Bitcoin and I was done. You can then obviously copy the truecrypt file off to wherever you like
If you're just having a prat about on it though don't bother
Another interesting feature with bitcoin, you will have a recieving address as default, but you're supposed to create more for different things, so you could have one as 'public' one as 'mtgox' for recieving money from there (assuming you use mtgox) infact every trade you ever get into, if you want you can create a unique address, the money always ends up in your wallet.