Go with Etrade or a comparable online trader.
They are insured by the FDIC, and although they do charge ~$9 per trade, they provide
so much research material.
Have at least $1000 to invest. Commissions do get at your profit and it's hard to be diversified with less than a grand.
Also, invest in something you know. An hour after this
Gizmodo story broke, I bought Apple at $243.93. I know when they realease the iPhone 4, theyre profits will skyrocket, and so will the stock price. So buy what you know. Also, luckily for me, their quarterly earnings came out the day after I bought it, and shattered expectations.
It'll help to experiment with a free trader, like Google Finance. You can setup a portfolio and see how it does.