Imus is suing:
"Now comes Imus with a contract. I've heard his lawyers detailing what is in the contract. It is clear that he should have been warned by CBS if he were to have been fired. It is also clear that CBS knew what it was getting with Imus. Words in the contract revealed that Imus would be shocking and provocative and so on. CBS no doubt will argue that what Imus did crossed the line. Imus apparently is suing for big bucks. He may get millions. If so he would have the capital to put together a network of his own. If that sells again Imus would be wealthy and the public would be stuck with him again.
Source
I have no brief for Imus but I suspect that it would be good for free speech if he wins this one. It could at least make media magnates more cautious about firing people for incorrectness.