Stocks are edging lower today on weak earnings and continued worry over the eurozone credit crisis. Fitch Ratings downgraded Greece by two notches this morning, Pushing the country's rating further into junk territory.And the indices are all in the red today - The Dow Jones industrial average is down 47 points in mid day trading. It broke through 13,000 in yesterday's session for the first time since May of 2008, but hasn't been back up there today. Also slipping, the S&P 500 fell five and a half points. And the Nasdaq sank 16 points.European stocks were lower in afternoon trading. The FTSE 100 slipped 0.3%, the German DAX dropped 0.6% and France's CAC 40 edged 0.3% lower.Looking back to the NASDAQ, the star performer today in a sea of red is Sourcefire. Its up 22 and a half percent. Sourcefire is a network security company. It surged on demand for protection against cybercrime. And that drove it's first-quarter revenue forecast above analysts' estimates.On the corporate front, earnings season continues. Dell reported results after last night's close, missing analysts' expectations. Shares fell almost 7% in early trading this morning.And after today's close we'll hear how rival, Hewlett-Packard is doing with their quarterly earnings. HP is expected to post earnings of 86 cents per share, down from $1.36 a year ago. In tech news, Apple's shares are slipping, down 7 tenths of a percent as the tech giant faced Chinese company Proview International in a Shanghai courtroom. They alleged that Apple doesnt own rights to the iPad trademark in China.And in economic news, home prices are at their lowest point in ten years. the median home price in January fell 2% from DecemberAnd that's the lowest price reading since November of 2001, before the run-up in home prices that became known as the housing bubble.One bright spot here is news that existing home sales rose 4.3% last month.