Besides a monetary donation to the USO, what are some ways to provide
support to our troops, like organizations that will accept food and
toiletries and create care packages?  (I'm in Brooklyn if you're
thinking locally.)

Hi! Thanks for the question.

Here are the organizations that will accept and even make care
packages which you can send to US troops around the world. In some of
them you may pay at the websites themselves so it doesn't matter
wherever you are located.

Care for Troops
http://www.care4troops.com/

Care Packages to US troops
http://www.west-point.org/parent/wppc-st_louis/ICarepackages.htm

CarePackages.com
http://www.military.carepackages.com/site_pack_detail.ilx?idProduct={43204F16-FECC-4ED6-8E18-3C2868270A39}

Support US Troops
http://www.supportustroops.com/products.htm

Operation Smile Box
http://www.military-carepackages.com/stores/store.xfm?store_id=576&page_id=5

In terms of cash donations you could send them to the following
organizations.

Coast Guard Mutual Assistance 
http://www.cgmahq.org/

Air Force Aid Society
http://www.afas.org/body_contribute.htm

Navy-Marine Corps Relief Society
http://www.nmcrs.org/helping.html

Army Emergency Relief
http://www.aerhq.org/qa.asp?a=16

Support The Troops Campaign
http://www.supportthetroops.com/Page4.html

Search terms used:   
support US troops "care packages" donations
  
I hope these links would help you in your research. Before rating this
answer, please ask for a clarification if you have a question or if
you would need further information.
  
Thanks for visiting us.   
  
Regards,   
Easterangel-ga   
Google Answers Researcher

Thorough and quick answer.  Great service, easterangel!

Thanks for the nice rating and for the tip!