The iPhone versus Android debate reached a new level Monday when technology titans Apple and Samsung went to federal court over their strikingly similar, billion dollar products.

Apple Inc. filed a lawsuit against Samsung Electronics Co., the largest tech company in the world, last year. The company accused Samsung of stealing the designs and software on their phones and tablets from Apple's popular iPhone and iPad products. The Cupertino-based company is demanding $2.5 billion in damages, an award that nearly doubles the largest patent-related verdict to date.

Samsung filed a counter-suit, alleging that Apple also profits from stolen ideas.

After picking a jury yesterday--seven men and three women--both sides will offer opening arguments today.

The two companies also are facing off in courts in Germany and the United Kingdom. The high-profile case is one of some 50 lawsuits among a myriad of telecommunications companies trying to get a leg up in the burgeoning $219 billion market for smartphones and tablets.

Back in the United States, District Judge Lucy Koh in San Jose ordered Samsung to pull its Galaxy 10.1 tablet from the U.S. market last month, pending the outcome of the trial. But the judge barred Apple's attorneys from telling jurors about the ban.

"That's a pretty strong statement from the judge and shows you what she thinks about some of Apple's claims," said Bryan Love, a Santa Clara University law professor and patent expert. Love also said that even though 10 jurors will decide the outcome of the case, the judge has the authority to overrule their decision if she thinks it's wrong.

Mark A. Lemley, a Stanford Law School professor and director of the Stanford Program in Law, Science, and Technology, says that a verdict in Apple's favor could send a message to consumers-Samsung's Android-based products are in legal danger. However, a verdict in Samsung's favor, especially if it prevails on its demands that Apple pay its asking price to certain transmission technology it controls, could lead to pricier Apple products.

Lemley, along with other legal observers say it's rare for a high-stakes patent battle to actually go to trial. Court-ordered mediation sessions attended by Tim Cook, Apple's chief executive, and high-ranking Samsung officials failed to resolve the legal dispute. The failed attempt at mediation led to what will be a highly technical trial of mostly expert witnesses lecturing on patent laws and tech speak. Cook is not on the witness list and is not expected to testify during the trial, which is expected to last four weeks.

In court papers filed last week, each company laid out its legal strategy in trial briefs.

Apple lawyers argue there is little difference between Samsung's products and Apple's and that the South Korean company's internal documents prove it copied Apple's iconic interface and design.

"Samsung once sold a range of phones and a tablet of its own design," Apple lawyers argue. "Now Samsung's mobile devices not only look like Apple's iPhone and iPad, they use Apple's patented software features to interact with the user."

Samsung denies the allegation and counter-charges that Apple copied its famed iPhone from Sony. Samsung lawyers noted that the company has been developing mobile phones since 1991, while Apple didn't jump into the market until 2007.

"In this lawsuit, Apple seeks to stifle legitimate competition and limit consumer choice to maintain its historically exorbitant profits," Samsung lawyers charge. "Android phones manufactured by Samsung and other companies - all of which Apple has also serially sued in numerous forums worldwide - offer consumers a more flexible, open operating system with greater product choices at a variety of price points as an alternative to Apple's single, expensive and closed-system devices."

Between the patent sniping, the most notable thing about this trial may be the fact that it's happening in the first place.

In the technology industry where so many companies hold many vital patents needed by all players, lawsuits are viewed as toying with "mutually assured destruction," Love said. Most disputes are solved through "horse trading" and beneficial agreements to share intellectual property and royalties.

Love, Lemley, and other observers note that Apple's motivation might come, in part, from Steve Jobs, the company's late founder and iconic figurehead. Jobs claimed any company using Android technology to create smartphones and other products was brazenly stealing technology from Apple.

Samsung attorneys wanted to use Jobs' statements from Walter Isaacson's book "Steve Jobs,"published several months after the Apple leader's death. But the judge barred the statements from trial earlier this month.

"I will spend my last dying breath if I need to, and I will spend every penny of Apple's $40 billion in the bank, to right this wrong, I'm going to destroy Android, because it's a stolen product," Jobs is quoted as saying in Isaacson's book.

"I'm willing to go thermonuclear war on this."

The Associated Press contributed to this story.