I've been searching for this drama CD for a long time; I looked for it in many stores while I was in Japan and never found it. I'm thinking about giving in and buying it on Amazon even though it's ridiculously expensive brand-new.
Luckily Geoviki directed me to an Italian forum, Mundo Yaoi, where I was able to download it! I will also re-upload it and share it here, just in case, since it looks like there are a lot of broken links that no one repaired on their site.
EDIT: I've since purchased the CD for myself as well. Found it on sale at Bookoff for only 280 yen (about 3$!)
Download: Link Here!