Time conversion across various parts of world

Hello,

For example, our website is running on a server located in Japan and we have
another website #2 running in US. our database is located on the server in
Japan. when some one accesses our website #2 which is located in US, the time
at which the user accessed our website #2 has to be registered in a database
which is situated in Japan. but at present i am getting the system time of the
server which is in japan.  How can i convert this time or get the corresponding
time at US using pgsql time zone feature or if anything else.

Please note: Our other website#2 can be located in other parts of the world
also, it need not be US only. I have the country name where our  website#2 is
located and by using this name i need to get the time in that country.

we are using postgresql 7.3.4.

Eagerly waiting for replies.

Thanking you,
deepthi