is it legal to use words "ebay" or "google" in a domain name

[wxdqz]

Hi,My question is as in the subject. I have seen some sites running with ebay and google in the domain names. But how far they are legal ? I plan to use a domain name with ebay word in it. However, i am going to create a store of ebay only in it.Thanks for the help,Regards,Yajunithish