I agree. Its better to get a pre-paid SIM from the destination country.
You will get free incoming calls and much cheaper local rates.
in most cases calling back to US is very cheap compared to using a US based
phone overseas or renting a phone.
If you are in US,
www.newegg.com has some unlocked phones.
if you already have a T-mobile or Cingular, you may be able to call them
and have it unlocked (if its a tri/quad band phone).
Check out
www.expansys.us, not the cheapest, but they have an
extensive list of mobile phones and accessories.