...in different countries? I have been traveling frequently lately, including overseas, and I would like to have my own portable wireless Internet instead of depending on wifi.

I know that some cell/mobile phones can be used as modems, and I have owned a Verizon wireless USB modem.

However, roaming from country to country with such a modem is very costly, even if you get an international plan with your provider. Vodafone, for instance, charges 90 Euro per month for just 200MB.

I have been considering some unlocked phones and getting SIM cards in countries I visit, and probably using pay as you go / top up in each such country.

Can an unlocked, modem capable phone with a local SIM card from a particular country be used as a modem to get online in that country?

If there are any special tech concerns, what are those?