Well...Xbox360 also trademarked by Microsoft. But there are many site like: www.planetxbox360.com www.myxbox360.com www.xbox360forum.com etc. is there any way to find out for sure?
Using "Oracle" depends on the usuage. You certainly can't use it if it has anything to do with Oracle's business or sector. If you are going to sell hummingbird feeders, then you probably wouldn't have any problem. Just because other people do not have permission to use a name, it doesn't mean is legal.... i.e. there are a lot of kiddie porn sites but no one is going to argue they are legal just because they exist. A lot of people used "MySpace" in their domain name and they are now getting C&D letters. A company can sue you for all your income and get treble legal fees for trademark infringement, so you are always taking a risk. Most of the time, you will just be forced to surrender the domain and lose the site - but that is up to the trademark holder.
No you will be fine. I think you would be much better off with a software or database directory on that domain. Adsense returns would be much better.