The legal battle between Apple and Psystar over copyright infringement heated up this week, after the Florida-based Mac clone manufacturer took testimony from Apple head of marketing Phil Schiller, and announced that it has lined up other executives for next week.

The dispute concerns Psystar's manufacturing of so-called 'Open Computers' which it preloads with Apple's Mac OS X Leopard operating system. Apple has argued that the licensing agreement for OS X does not allow for third-party installations.

The agreement reached by the pair this week to allow Psystar lawyers to take depositions from top Apple executives signals a new stage in the legal dispute, and will see Psystar try to gain the upper hand through the testimonies.

During the coming week, Psystar's lawyers will grill Mike Culbert, senior director of Mac hardware, Simon Patience, head of Apple's core operating system development, and Bob Mansfield, senior vice president of Mac hardware engineering.

Psystar has also taken the unusual step of asking anyone with an interest in the case to send in suggested questions to ask the Apple executives.

"After numerous depositions of Psystar employees and associates, the shoe is finally on the other foot. Oh the joy," Psystar said in a blog post entitled A taste of their own medicine.

"Feel free to post your questions as comments or email them directly to press@psystar.com if you feel that the question would be better unleashed via surprise attack.

"Bear in mind that we might not be able to release the answers to said questions until the conclusion of this litigation (re: Apple's Super Secret Protective Order) but we are still allowed to use them amongst our legal counsel and in court."