I recommend a cheap Motorola quadband. Avoid the v600. The phone has had problems. There is a thread going on Ipods, European Power Adapters, etc. where people discuss a number of options.

I actually prefer Nokia phones, but for reasons that escape me, only Motorola does quad bands in the inexpensive lineup. I think Motorola must hold a critical patent here that others are forced to license. Motorolas also work well with the callback routines built into many of the international roaming SIMs.