If I have a corporation in one state, and my employee who also resides in that same state but works less than 60 days in a calendar year in California, is that employee subject to California state taxes? If that same employee performs no work in their resident state but works the 60 days or less in California, who is responsible for paying the workers comp and the unemployment deductions? And to what state is the deductions/payment assessed to?

Income earned by the employee while present in CA is CA income. The employee must file CA tax return and report this income.
The employee will report his worldwide income including CA income to the resident state. He/she will also claim credit for taxes paid to CA. Your U.S. Tax Return: Working or Living in Two or More states (http://taxipay.blogspot.com/2008/06/working-in-two-or-more-states.html)

I think it really depends on the nature of the work during those 60 days in CA. If the employee has an office, phone, etc in CA so that the CA is essentially a 2nd work location then I agree with Mukata. But if the visits are temporary, the employee does not have an office in CA, he files expense reports for his T&L for visits to the office in CA, then I think he does not need to pay CA income tax for these business trips.