Van D sorry you are having troubles; I just bought a new MacBook and was reviewing this thread to install my HP onto the new notebook. When I got to step "4" and click the "+" to add a printer, again the "Photosmart C6100 series [94D900]"comes up with "Bonjour" under kind.
If you are unable to see your printer at this point, then it would appear that your printer isn't being recognized on your network. My suggestion would be to go to your 6180 and run through the menu settings and reset everything back to default values; it seems that for some reason your printer isn't able to utilize the Bonjour technology (
http://www.apple.com/macosx/technology/bonjour.html).
There may be a problem with your router/firewall technology blocking this (
http://discussions.apple.com/thread.jspa?threadID=700851&tstart=251).
If default printer settings don't help, you might try isolating your problem by turning off anti-viral/firewall settings and trying this.
Another option I might suggest is to assign your HP6180 a permanent IP address on your network; that is what I did in addition to the other steps in the solution provided.
Hope this helps; please post a reply after you try, and let me know your outcome.
Best of luck, and Happy New Year!