As a for instance:

# rpm -Fvh glib*
warning: package glibc = 2.3.2-4.80.6 was already added, replacing with glibc <= 2.3.2-4.80.6
warning: package glibc-debug = 2.3.2-4.80.6 was already added, replacing with glibc-debug <= 2.3.2-4.80.6

How do I know if the .i686.rpm or .i386.rpm version of these packages were installed here? I've always manually selected the i686 version (these are RedHat 8 patches in the example) when there have been optimizations available for both CPU architectures.. Does rpm handle this for me though? How does it know if so?

The "bible" for RPM is Maximum RPM.

# See rpms installed on current system
rpmquery --all | more
rpmquery --all > <filename>
rpmquery --all | grep -i <plaintext>
Autospec for tarballs
RPM tools
# Redhat links
RedHat Linux Manuals
Get your mp3 support here
Maximum RPM
rpmfind
Easier software management: apt4rpm - Red Carpet
RedHat 8.0 Tips & Tricks

# Redhat 7.3 down configuration commands
setup leads to several configuration tools

# Redhat 7.3 up configuration commands
Configure soundcard:
redhat-config-soundcard
Configure X server:
redhat-config-xfree86
Configure network:
redhat-config-network
Manage software:
redhat-config-packages

# Handling NTFS
New Technology FileSystem (NTFS) HOWTOs
Linux NTFS project

"Does rpm handle this for me though?"

No. You have to handle it yourself. Rpm handles package name and version number. It does not hand i386, noarch, and such.

I guess the way I should have phrased that is this:

If I rpm install or update with a * and it pattern matches both an i386 optimized and i686 optimized copy of the same version of the same package, will it go for the 686 one if the CPU is appropriate or will it always go for the least common denominator? I'm suspecting 386 every time, just wondering if someone knows for sure.

Thanks.