The short answer is that you SHOULDN'T set up a mining rig to mine bitcoins, if all you want to do is USE bitcoins.
Simply buy or trade for them. The easiest way to do that, in my opinion (from a US-centric perspective) is to set up a Dwolla account, transfer a bit of money from your bank to Dwolla. Then transfer that money from Dwolla to an exchange (Mtgox and TradeHill are two examples), and then buy bitcoins at market rate.
Then you can use them to buy goods and services (including namecoin names). Bitcoins are the "currency". Namecoins are sort-of related (using the same underlying technology), but are a separate product.
Simply buy or trade for them. The easiest way to do that, in my opinion (from a US-centric perspective) is to set up a Dwolla account, transfer a bit of money from your bank to Dwolla. Then transfer that money from Dwolla to an exchange (Mtgox and TradeHill are two examples), and then buy bitcoins at market rate.
Then you can use them to buy goods and services (including namecoin names). Bitcoins are the "currency". Namecoins are sort-of related (using the same underlying technology), but are a separate product.