Speaking of the holidays, if you are sending a package to loved ones stationed or deployed overseas, the USPS released some very important dates to keep in mind:
*UPDATED with 2012 dates*
The graph above is what's suggested by the USPS to get your gifts overseas by Christmas, but it is highly recommended to get those packages out before the dates listed. So the best rule of thumb for sending out those gifts is the sooner the better!
Also keep in mind that any box you ship out needs to have a customs form with it. If you've never filled one out before, they can be pretty daunting, especially with military addresses overseas.
I quickly made a fake address up to show you an example of what you need to fill out:
(this is a completely pretend address)
ABC 123 BOX 456
One important thing when filling out the address: please don't write the actual destination country on the box or on the customs form. It will only hold things up and take much longer to reach the destination. This hasn't happened to us, but I know several people who have waited months for packages to get to them and the only thing they can think of for the long delay is that the country was written out!
As far as shipping goes, flat-rate "if it fits, it ships" boxes are pretty handy. Basically, stuff as much as you can into one and play a flat-rate fee to send it. Small boxes (they're really tiny, by the way) are $5.35, medium (two versions) are $11.35, and the large size (two versions) are $15.45 when sending to an APO/FPO address ($13.45 within the states).
Flat rate boxes (and customs forms) are free from the post office; you can just walk right in and take how many boxes (in whatever size) you need or you can order them from here for free (I think you have to pay for shipping).
I've also heard (but have not confirmed that they are still doing this) that the post office also offers free military care kits that includes two large and four medium boxes, six labels, one roll of tape, and six customs forms. You can apparently request this by calling 1-800-610-8734. *UPDATE: this was still true in 2011; I'm not sure about now, in 2012*
A few other things that may be good to know: if you are mailing something to someone at a military base overseas (APO/FPO), you will pay American prices, not international prices. It's just like sending something across the country (pretty great, right?)! It also might be cheaper for you to send it in a regular ol' brown box (not in one of their spiffy flat-rate boxes) if what you're sending isn't very heavy!
So there you have it—a quick overview of sending packages overseas! I'm sure I missed some things, but hopefully it's a good start. Post office workers are usually pretty patient and will help you out if you have questions about filling out the customs form or sending something overseas in general.