OGam3r RSS Reader
The OGam3r RSS Reader will retrieve your ingame messages via RSS feed, and notify you of any events, such as spying or attacks on your planet.
You can check here to see how it looks and read more about it.
It would be nice to see some other features, like sending emails when you're being attacked, or status of production/research or similar. Or at least combine the author's other project, OGame Ninja Timer with this.
Of course, it's not free: you'll have to dish out $10 to use it for 3 months, so it may not look so appealing, but if this is something you've been looking for, you're welcome to check it out.
I can't try it out so I got no idea if and how exactly it works, so don't blame me if it turns out to be something you didn't expect. For any concerns you might have I recommend mailing the author and asking him.