It's in limbo too, more or less. I think there have been court cases going both ways, declaring the shrink wrap licenses invalid or valid. A few states have passed explicit legislation (UCITA) to give shrinkwrap licenses more validity.
Some info on UCITA:
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Offices/ALA_Washington/Issues2/Copyright1/UCITA/UCITA_101.htm
As I understand it (IANAL!), many shrink wrap licenses don't even meet the requirements for a valid legal contract. I don't know if the licenses that have been declared invalid were declared invalid on that ground, or because they contained terms that wouldn't be enforceable even in an otherwise valid contract.
It might be worth the OP's time to post to misc.legal.computing or misc.int-property for more information. Hiring a lawyer might be smart too.