Loaded the lastest rubygems (0.9.0) as root, like always,
but in my USER account I can't see it anymore.  I have no
problem doing this on my laptop.  The only difference is I'm
using ruby 1.8.5 in my USER account, while the root has 1.8.4.

I'm using PCLinuxOS 0.9.2 on my desktop and 0.9.3a on the laptop.

In both cases gem was placed in  /usr/bin/gem and the PATH is set
to see this dir in both case.  But when I run the gem command from my
desktop I get the following message:

$ /usr/bin/gem
/usr/bin/gem:10: unitialized constant Gem (NameError)

or 

$ gem
bash: /usr/local/bin/gem:  No such file or directory