Tech blue chip Apple (NASDAQ:AAPL) has been on a roll lately, dominating market headlines by breaking market milestone after market milestone. First the company made headlines by breaking through $500. Next, the company’s market capitalization topped $500 billion and the latest news was that Apple briefly broke through $600 billion, trading at a new all-time high.

But the latest headlines are a little tougher on the tech giant, after the Department of Justice filed a lawsuit that accuses the company of price-fixing in the ebook market.

Also named in the suit were publishers HarperCollins, Simon & Schuster, Hachette, MacMillan and Penguin. The first three publishers settled immediately while Apple, MacMillan and Penguin plan to fight on in the legal proceedings.

Now, I don’t see much to worry about here for Apple, since the government’s case against the company is much weaker than its case against the publishers. Plus, Apple is just a distribution point for the books — and a relatively small one at that, considering that Amazon(NASDAQ:AMZN) takes up as much as 90% of the ebook market.

So take the opportunity to pick up a few more shares of Apple. The stock is still trading at just 14 times its expected earnings for the next year — in line with the industry average and actually less than the NASDAQ’s price/earnings ratio.

As I’ve discussed, the real growth for Apple is in its new products — like its entry into the 4G market, its new Retina display that trounces the resolution of any other handheld gadget on the market and the potential for a full-fledged Apple television set.

Keep tabs on AAPL shares using Portfolio Grader, and continue to check in here for additional updates on this exceptionally profitable company.