I have an Apple Mac ibook G4 primarily for home use.  We (family)
connect to the internet though a cable modem and the Airport Extreme
(creating a wireless, home network).  Soon, I plan on purchasing a Mac
mini (Intel Solo Core) for my child, which will also connect to the
same home network.

I'm looking for an external hard drive to share file (songs, videos,
MS Office files, etc.) which both computers could access on the
network.  Though it wouldn't be a problem tethering it to the mini, I
don't want to have to connect my iBook via firewire or USB everytime I
want to access the external harddrive, so I'm looking for something
that will connect wirelessly to my newtowork.  The other advantage is
I could place the drive in closed shelf, reducing clutter and freeing
up desk space... likewise, other shared storeage options (i.e., high
capacity USB thumb drive, for example) aren't pratical - again having
to physically connect it to either the iBook or the mini everytime we
needed to use it is not ideal.

What devices are out there?  Price and reliability are other factors.

Ok I am in kind of the same situation, however I have a macbook that
uses my wireless network and I want a network hardrive. Since you have
a ibook and a macmini I think I have a solution for you. Why dont you
take the mac mini and add a firewire (or usb) harddrive to your
macmini and then share it on your network. That way you will be able
to access the storage through the mac mini and the ibook    and you
wont have to have to ibook hooked up to any wires. The mac mini will
have to always be on though. Hope this helps.