sikandar,

what you actually want to do is kind of cloaking but you do not only distinguish human visitors and bots but to go a little more complicated. If the search engine is always shown the same content and only human visitors are redirected to different sites, there should be no problem until a human revision takes place.

You need 2 databases for that:
IP geolocation database
searchbot database (e.g. fantomaster.com or free available... but... more risk)

best thing in your case is that you write your own script, I don't think there is a script that deals with both things - geolocation and cloaking. Actually it is quite simple to archive that, check $_SERVER['REMOTE_ADDR] for the IP, decide if it is a bot or not, and redirect with php-redirect