Any competent car radio installer can replace your existing radio with
an XM-capable one in the same slot. (unless it is integrated with the
AC, like the Accord Nav system is) I think Honda radios are Alpines,
so depending on your model they may be able to add an Alpine satellite
tuner to the factory radio.
They will need to add a tuner box and antenna. You won't see the tuner
as it usually is tucked under a seat (the XM channels will be changed
from the radio in your dash). The antenna will need to be in a place
where it can see the sky, so it will be a visible add-on.
The XM-tuner/antenna will probably run about $100-$150, and the
replacement dashboard radio (depending on your features) can run from
$100 into the thousands. A $150 radio will be similar in features to
the factory one. Labor is maybe $100 as well so overall the
third-party price could be as low as $300.
A competent installer should be able to take a look at your car and
outline your options.
I had no problem with this add on in my 02 RSX, and 98 Civic.