Recently trying to solder SMD parts for a diy-able low-cost-per-deployment-arduino-board (which can be found here: http://bluesceada.blogs.ghostdub.de/2010/12/23/freeduino-etching-at-home/ ). Problem’s to get the SMD parts clean on it with a old/bad solder-iron… some cheap flux came to rescue! With flux – even if it’s cheap (i bet you guys out there using better flux wouldn’t want to solder using something like that) – even the ftdi chip was no problem at all! I just ebay’ed for a cheap large package and found thingies like http://img.auctiva.com/imgdata/1/1/4/5/0/1/0/webimg/408441030_o.jpg which are meant for xbox rrod fixing … it works, seems to be made by a well known company (balverzinn, try googeling for the product-id on the package)!