This is irrelevant in this case since Apple's EULA for OSX is readily available on their website before purchase. Not to mention that Companies are not exempt from EULA's if they get in the business of reselling - they just cannot claim ignorance after the first violation - after that its willful neglect.
Individuals might get out of an EULA, but they have been found to be valid - and I would bet that they are considered contracts for businesses.
Well, an EULA is what it says: An END USER license agreement. A reseller is not bound by the terms of any EULA, since a reseller does not use the software but only (re-)sells it, and Psystar is not the end user of the version of OS X that they (re-)sell to their customers.
Furthermore, OS X is available on the market in RETAIL boxes that can be purchased by anybody. Unlike some have stated here, it says NOWHERE on a retail box that it is an UPGRADE - which would imply that you --might-- need an older software version to be eligible to purchase the software. Apple does not sell upgrades or updates, they only sell full (retail) versions of their software.
And now Psystar is reselling retail versions of OS X and patches those versions to make them run on their own hardware. Which are two different legal actions, just to make this absolutely clear. One is reselling the software, the other one is installing and patching that software on the computers they sell to their customers.
They do not have an OEM contract with Apple, but neither has Amazon or Gravis, the biggest German Apple reseller, or anybody else who is selling Apple products. Still, Amazon and others are selling retail boxes of OS X anyway, because it can be traded freely. Without any doubt, it is absolutely legal that Psystar sells a retail box of OS X to their customers.
That only leaves the EULA situation and the patching of the software in question.
In some cases, certain EULAs might be valid. In other cases - and in other countries - certain EULAs have been found to be invalid and even illegal. Apple's EULA has not been challenged before, and currently it is only being challenged in the United States. Maybe Apple will win in the US, but that doesn't mean that there EULA will be found valid any other country of your choice as well.
The same goes for changing the code of some software to make it work. In many countries (including Germany) it is perfectly legal to patch a software to make it work without a hardware dongle (as for example a USB key) - provided (and that is important) that the dongle causes compatibility issues with other software or hardware on the system and, of course, that you own a legal license to the software (which Psystar customers do). And it seems that even the American DMCA has more holes than a swiss cheese, so it'll be interesting to see if Apple is only clutching at straws here or if the DMCA will actually back their claims. Furthermore, Apple is giving away major parts of OS X (namely the Darwin UNIX foundation) under an Open Source license, and it certainly is not illegal to modify open source software.
I think Apple is standing on very shaky ground here, and their best chance for winning this case is only the fact that US-American laws and the US-American jurisdiction are extremely corporate friendly, to put it mildly.
And to all the "Go, Apple, Go!" screamers: You really must enjoy living in a cage. And you even pay money for living there. You're cheerleading for a company that files lawsuits to take away or at the very least significantly restrict YOUR rights to use the stuff that you have bought with your good money. It's like buying a book for double the price, but you are only allowed to read it in a Starbuck's shop - and at the same time you hate the little company that wants to sell you the same book for half the price and you'd be allowed to read it anywhere you like. Why? Because it's no longer special when anybody can have it on any machine? Does that make -you- less special? It's in the best interest of everybody if Apple loses this lawsuit.