Definitely look on ebay for unlocked phones. I always find that in the States,
the selection of mobile phones seems very limited. On my trips to HKG, I am always amazed to see the huge selection of hand phones. Some never make it stateside.
Three weeks ago when I was in HKG, I bought an unlocked (which all phones are in HKG), Nokia 7270. It's stylish, user friendly menu, tri-band, etc.
http://www.nokia.com.hk/nokia/0,,63124,00.html