hey,

seems like an ambitious challenge :) well you can use PHP to do what you 
want. as far as recognizing the country or region the user lives in is 
besed on ip addressing. for example one country can be using class C 
network ranging say from 162.-.-.- to 174.-.-.- etc. you need to find out 
how do these really work (ip addressing). if you are looking for some 
resources regarding PHP and NETWORKING check out www.php.net, there's 
also very good book - PROFESSIONAL PHP 4 BY wrox - there you should find 
a chapter about networking....

php has some functions that will help you out (networking): 
gethostbyname(),
gethostbynamel(),
gethostbyaddr(),
getprotobyname(),
getprotobynumber(),
getservbyname(),
getservbyport(),


hope that helped... 

voytech