check out this site for an alternative to regular fanny packs:
http://www.thewilderness.com/safepack.HTM
Fanny packs generally scream GUN! to me, but mostly in locations where you are less likely to need a full-sized one. On the trail or in the woods, they blend in.
For smaller guns like my 640 S&W or Glock 27, I like Uncle Mike's Gunmate belt pouch. Doesn't look like a gun pack, is small, and has a separate hidden compartment for the gun. Then, you can make a show of accessing the main pouch for your wallet, keys etc in front of people. They'll never suspect.imho