What options are available, officially or unofficially, to use a
Blackberry wireless device with a network full of PowerMac G4's
running Mac OS X. Connectivity would need to be USB (with or without
an adapter). Obviously a conduit needs to be obtained.

Hey macsamurai! :)

Im a linux user, so I can understand how you feel :)
I found some info:

Check:

http://www.pdastreet.com/boards/RIM-Blackberry/messages/613.html 

and 

http://www.rimroad.com/boards/General/messages/617.html

Those posts have the email addresses of the posters. maybe you can try
to contact them!

I'm afraid I can rule out the "official" channel for you.  I got this
reply today from RIM's technical support:

"The BlackBerry Desktop Software currently runs on 
Windows 95/98, Windows NT and Windows 2000. RIM currently does not 
offer a Mac version of the Desktop Software. To deliver
synchronization of
calendar, address book, tasks, and memo pad, RIM licenses Intellisync
software from Puma Technologies. At this time, Puma does not offer a
Mac
version of Intellisync. There is currently no timeline set for the 
introduction of Mac versions of Intellisync or the BlackBerry Desktop
Software. "

How about using Virtual PC?

Hello,

Epicad (www.epicad.com) will soon release the wireless synchronization
software to sync contacts (address book), TODOs and events with Macs
(OS X).

Hello all,

I've been follwing this thread for a bit now and wanted to share
something that showed up in my inbox...

The PocketMac (who make Mac-to-Pocket PC sync tools) people just
announced a BlackBerry sync solution for $30. I haven't tried it yet,
but will report back here as soon as I have. Ther site is
pocketmac.net

Since I'm not going to have my BB for a few weeks, I thought I'd shar
it here. I have no idea how long it's good for, etc.

Yay! A solution! Yay! :)

Ted

I am currently using PocketMac to sync iCal, iCal Tasks, Address Book,
and Stickies (to dos) to my Blackberry 7290. I have had great success
and love the product. My cell provider (Cingular) also supports
multiple email accounts in their data plans, enabling all my IMAP
accounts to be accessed from my Blackberry.

There is also a company called Epicad that makes a sync utility
(SyncAgain), but I haven't any experience with it.
http://www.epicad.com/syncagain/

The ability for us Mac OS X junkies to sync to our Crackberries has
been a long time coming... I am quite happy, and very productive, for
now.

Chris