If you get a Honda OEM CD changer, there is a mounting kit that fixes it solidly to the car. With the kit, I think the installation is not too difficult. There is also a post here:
http://www.insightcentral.net/owners/mods/cdmount.html
where someone didn't use the mounting kit.
I bought an aftermarket CD changer from another lister here at Insight Central. Electronically it was fine and the cables attached directly into the back of the head unit. I was going to try the mounting system from the above link, but I discovered that the dimensions of my CD changer were slightly greater than those for the OEM changer. I cut the foam as described above and THEN fabricated a mounting bracket out of sheet metal. It has worked great, but it was a pain in the neck to bend and install.
Good luck.