This is probably something really simple but I'm a newbie. I'm trying to install a plug-in for gaim and when i run ./configure on the source it's giving me the following error:

*** The pkg-config script could not be found. Make sure it is
*** in your path, or set the PKG_CONFIG environment variable
*** to the full path to pkg-config.
*** Or see http://www.freedesktop.org/software/pkgconfig to get pkg-config.
configure: error: Library requirements (gaim >= 1.0.0) not met; consider adjusting the PKG_CONFIG_PATH environment variable if your libraries are in a nonstandard prefix so pkg-config can find them.

I have Gaim v1.0.3-0.FC3, but apparently it can't tell that because something is messed up with where it's reading it? Any help you guys can give me would be greatly appreciated, thank you.

You just need to install pkgconfig - just follow the link to download and then install it.

I just installed the newest version and it's still giving me the same error. I've tried running as root and also as my user. I even rebooted (which I'm not sure is necessary or not but I did anyway).

You shouldn't need to reboot - where is the binary installed? Make sure that it is in your PATH variable (echo $PATH) or link it into your path.

How would I do that? sorry I'm still getting the hang of all this. When I do echo $PATH I get:

/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/home/grimey/bin

The easiest way is probably with a symlink:
ln -s /path/to/pkg-config /usr/bin/

Alright that worked, but now I'm getting a different error.

checking for gaim >= 1.0.0... Package gaim was not found in the pkg-config search path.
Perhaps you should add the directory containing `gaim.pc'
to the PKG_CONFIG_PATH environment variable
No package 'gaim' found

configure: error: Library requirements (gaim >= 1.0.0) not met; consider adjusting the PKG_CONFIG_PATH environment variable if your libraries are in a nonstandard prefix so pkg-config can find them.

How would I add the path for gaim to the PKG_CONFIG_PATH? Thanks again for your help, it's much appreciated.

I also set the PKG_CONFIG_PATH variable to include /usr/lib/pkgconfig which is where gaim.pc is located and i looked at gaim.pc and it says the version is 1.0.3 so I'm not sure why it's saying it can't find a gaim version greater than 1.0.0

To set the PKG_CONFIG_PATH I simply did PKG_CONFIG_PATH=/usr/lib/pkgconfig, maybe I should have done something else?

You will need to export it so that other proccesses can make use of the variable - try:
export PKG_CONFIG_PATH="/usr/lib/pkgconfig"