Aye, those are some good sites. Besides them, I'm also a regular contributor at:
Friendly word of advice - it's a great and noble thing to send care packages to grunts. But please, lets not waste any huh?
What am I talking about? Well, please try and co-ordinate your efforts with some kind of agency. Not only does this cut down on 'prohibited' items (such as pork meats or raunchy magazines for example), but goes a great length to cut down on excessive duplication.
Some perenial items will never be refused - a good bet is chocolates, toilet paper, sports or automotive magazines etc.
One of the things I know (from personal and family experience - recently reinforced by my recently returned buddy) is the power of the simple letter. Mail call is always looked forward to. So if you think you can't contribute - think again!
Writing a simple letter to a soldier can work wonders!
I'm also a member at a MIL website - primarily developed to cater to MIL types and MIL families... but also open to the general public. Come meet the men and women who serve and their families and friends!
Interested? Send me a PM and I'll send you the link. It is NOT an "invite only" website - but I've posted the link in the open before and sadly I've had some outright trolls come by and create havoc and nuiscance. The website is created by an officer in the US Army (just got back from A'ghan not too long ago) and is run by MIL, MIL family and civillians and has a variety of members on board - international membership to boot