1)
Click new address, give it a name like "first deposit". Your public key will appear in the address textbox. This long string of letters and numbers looks like gibberish, because it is a cryptographic code. This public key can be copy and pasted, and it will be used by others to send you bitcoins. It is safe to give to others, they can't get coins from it, only send coins to it. You will be using it to send yourself bitcoins from your first bitcoin purchase in step 7.
2)
Start an account at tradehill.com or mtgox.com. If you go to tradehill and find this post helpful, please put
referral code TH-R18248. It costs you nothing and gets me a referral bonus that I earn by taking the time to write this post.
3)
Fund that account with US Dollars or other fiat currency. On tradehill.com this is done by clicking "Deposit Funds" on the left. Then you click your currency abbreviation in the middle of the page. Pick a deposit method. You may need to do some legwork with another website like Dwolla, liberty reserve, or paxum to get dollars in quickly. Or you can send a wire transfer, probably the quickest way for a first-timer like yourself.
4) [Wait for the funds to show up in your account. Depending on your deposit method this could take some hours or days.
5)
Place a buy order for X bitcoins at Y dollars, a price that is close to the current bid/ask spread. If you want to hold out for a lower price, put that price. Orders work like a good till cancelled order on an online brokerage like Etrade, for example.
6) Wait for the order to execute. Could take seconds or days depending on the spread between your desired price and current trading price.
7)
Send yourself the bitcoins. The coins should appear in your website's account balance once the order has executed. Then (on tradehill) you just click on "withdraw funds" on the left, click on "BTC Bitcoin Transfer" in the middle, put in the amount to withdraw, and
cut and paste your receiving address from step 1 into Box A, then click on "Request Withdrawal".
Wait for your coins. It will take 10 minutes, give or take, for the send to first show up with zero confirmations. This is after the website delay, which can be minutes or hours depending on how suspicious tradehill is of fraud lately. You will then have to wait for 6 confirmations to spend the coins, which takes about an hour. If your coins aren't showing up with the right number of confirmations, it is probably because your peer connections are lagging or your client isn't fully updated. You can check blockexplorer.com against the block # at the bottom of the client window to make sure you have the most up to date block. You can also file-->exit the client and restart it to get new peer connections that may not lag.
Alternatively, you could skip steps 7 and 8 and just leave the bitcoins in your tradehill.com account, then when you spend them do a "withdraw" to the recipient of the spend.
OK that's my help the newbies post for the week!