Great, thanks for the quick responses.  (And the great tool.)  I haven't gotten as far as installing make etc on my mac yet, so I'm just doing my development on the linux box.  As far as I can tell, this isn't a problem with the mac-ness or intel-ness, but rather the ruby version that came on my OS.  If I have any trouble after upgrading my ruby I'll repost. 

I may be doing something wrong here, as s3sync and ruby and my mac are fairly recent additions to my life.  s3sync appears to be skipping the upload step on my macbook (intel).  Identical code on my ubuntu box appears to upload.  Could it be missing a process for step or something?  Am I missing something?  Maybe this 1.8.2 ruby version is the culprit?

on mac: 
 ruby 1.8.2 (2004-12-25) [universal-darwin8.0]

on ubuntu:
 ruby 1.8.4 (2005-12-24) [i486-linux]


Here's my s3sync call (within a bash script):

# run test
./s3sync.rb -n -v -d --delete test/ cds_chf_listing_images_test:test/

Here's the output on mac:
----------------------
testing s3.
s3Prefix test
localPrefix /Users/corey/work/chf-s3/bin/test/
localTreeRecurse /Users/corey/work/chf-s3/bin/test
Test /Users/corey/work/chf-s3/bin/test/16911-1.jpg
Test /Users/corey/work/chf-s3/bin/test/16911-2.jpg
Test /Users/corey/work/chf-s3/bin/test/16911-3.jpg
Test /Users/corey/work/chf-s3/bin/test/17111-1.jpg
Test /Users/corey/work/chf-s3/bin/test/7211-1.jpg
s3TreeRecurse cds_chf_listing_images_test test
Trying command list_bucket cds_chf_listing_images_test max-keys 200 prefix test delimiter / with 100 retries left
Response code: 200
----------------------

Here's the output on ubuntu:
----------------------
testing s3.
s3Prefix test
localPrefix /home/corey/work/chf-s3/bin/test/
localTreeRecurse /home/corey/work/chf-s3/bin/test
Test /home/corey/work/chf-s3/bin/test/16911-1.jpg
Test /home/corey/work/chf-s3/bin/test/16911-2.jpg
Test /home/corey/work/chf-s3/bin/test/16911-3.jpg
Test /home/corey/work/chf-s3/bin/test/17111-1.jpg
Test /home/corey/work/chf-s3/bin/test/7211-1.jpg
local item /home/corey/work/chf-s3/bin/test/16911-1.jpg
local node object init. Name:16911-1.jpg Path:/home/corey/work/chf-s3/bin/test/16911-1.jpg Size:7635 Tag:2b9408c34765b6ac5902beba0b55ae80
s3TreeRecurse cds_chf_listing_images_test test
Trying command list_bucket cds_chf_listing_images_test max-keys 200 prefix test delimiter / with 100 retries left
Response code: 200
source: 16911-1.jpg
s3 node object init. Name:16911-1.jpg Path:test/16911-1.jpg Size: Tag:
Create node 16911-1.jpg
local item /home/corey/work/chf-s3/bin/test/16911-2.jpg
local node object init. Name:16911-2.jpg Path:/home/corey/work/chf-s3/bin/test/16911-2.jpg Size:7970 Tag:f7117281dc41f9d787d92dd4fc03a39a
source: 16911-2.jpg
s3 node object init. Name:16911-2.jpg Path:test/16911-2.jpg Size: Tag:
Create node 16911-2.jpg
local item /home/corey/work/chf-s3/bin/test/16911-3.jpg
local node object init. Name:16911-3.jpg Path:/home/corey/work/chf-s3/bin/test/16911-3.jpg Size:9952 Tag:6af98760f69416f9efce663d5b99df14
source: 16911-3.jpg
s3 node object init. Name:16911-3.jpg Path:test/16911-3.jpg Size: Tag:
Create node 16911-3.jpg
local item /home/corey/work/chf-s3/bin/test/17111-1.jpg
local node object init. Name:17111-1.jpg Path:/home/corey/work/chf-s3/bin/test/17111-1.jpg Size:8310 Tag:30d4590a1ff4065f5f555c19688ff71d
source: 17111-1.jpg
s3 node object init. Name:17111-1.jpg Path:test/17111-1.jpg Size: Tag:
Create node 17111-1.jpg
local item /home/corey/work/chf-s3/bin/test/7211-1.jpg
local node object init. Name:7211-1.jpg Path:/home/corey/work/chf-s3/bin/test/7211-1.jpg Size:9488 Tag:98e0c934f0d539957492ba982a5aad15
source: 7211-1.jpg
s3 node object init. Name:7211-1.jpg Path:test/7211-1.jpg Size: Tag:
Create node 7211-1.jpg
----------------------