I use Tide either liquid or powder depending on where I am going. I don't do powder internationally. Woolite doesn't do enough for me. Tide with a non-chlorine beach (as part of the product) does very well.

Minimus sells wee packets of Tide http://www.minimus.biz/detail.aspx?ID=7536 Try your methods at home before your trip to see how much product you really need. You can also fill up a couple of 3 ounce bottles.

In our office we also have a heat sealing machine used to seal items for shipment. I often make up little packets of liquid Tide into strips for traveling. About 1/2 ounch of Tide in each pouch works fine. I put those into my checked bag.