The XM satellites are in geosynchronous orbits parked over the East and West coasts of the US. The signal is "over the horizon" for Europe so there is no way to receive it.
Sirius satellites are in 12 hour, highly elliptical Molniya orbits, which are directly overhead of the US, and then Europe for 11 hours. Sirius only broadcasts when they're over the US though. If they were designed with enough power to broadcast over Europe, it's simply a matter of having transmit stations there to beam up to them. I have no idea if that's in the works.
Now that Sirius and XM have merged, They both broadcast the same programming.
Nothing stopping you from streaming through your mobile, on the other hand -- except not being able to sign up for an account, perhaps. Aside from sports coverage, there's nothing on Sirius/XM that you can't find somewhere else on the Internet and even then, its just a matter of paying for whichever sports you would like to follow. Check out flycast.fm if you have a smartphone.
Ok, thanks a lot everybody...
I'll try this advice, connecting a smartphone on the auxiliary, then connect my phone to internet and listening to streaming radios...
But I must have excellent connecting conditions while I drive, and in France, hi-speed connection is not available through all the country... So bad...
The best way I suppose is to record my favorite american radio and listening it after (not live but...)
Can I connect a hard drive ?
Thank you once again.