Unlocked phones ( any network phones) will work as long as it multibands.samsung corby i guess uses 4 bands eventhough its only 2g.... Yes it will work in uk..
If youre concern with roaming... It will still work..

if you like to txt somebody in the philippines and you have a smartphone or a pc and internet connection.... You can use CHIKKA. an application for free txting for your love ones in the philippines... 10 txts free a day but you can register unlimited IDs... One id one email address.... Create many email addresses and youll have many chikka IDs....:-:-)