This excerpt taken from the EBAY DEF 14A filed Mar 19, 2009.
U.S. Federal Income Tax Consequences and Other Tax Consequences
The option exchange should be treated as a non-taxable exchange for U.S. federal income tax purposes, and we and our participating employees should recognize no income for U.S. federal income tax purposes upon the issuance of the new RSUs. Recipients of cash payments will recognize ordinary income for U.S. federal income tax purposes on the date the cash payments are made to them, and the payments will be subject to applicable tax withholdings. The tax consequences of the option exchange in foreign jurisdictions will depend on applicable foreign tax rules and regulations but will be fully disclosed to participants subject to the tax laws of foreign jurisdictions as part of the offer to exchange options.